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Copper-diammonia, Cu(NH3)2, and its deuterated species, Cu(ND3)2, are produced in supersonic molecular beams and studied by pulsed-field ionization zero electron kinetic energy photoelectron spectroscopy and ab initio calculations. Structural isomers with a copper atom binding to an ammonia dimer or two ammonia molecules are obtained by the calculations. By comparing the experimental measurements to the theoretical calculations, the neutral and ionic forms of copper-diammonia are determined to be in a doubly bound linear conformation in their ground electronic states. The adiabatic ionization potentials of Cu(NH3)2 and Cu(ND3)2 are measured as 29 532 (5) and 29 313 (5) cm-1, respectively. The metal-ligand symmetric stretching frequencies are measured to be 436 cm-1 for Cu+–(NH3)2 and 398 cm-1 for Cu+–(ND3)2, and the metal-ligand bending frequencies 75/139 cm-1 for Cu/Cu+–(NH3)2 and 70/125 cm-1 for Cu/Cu+–(ND3)2. Moreover, the dissociation energy of Cu(NH3)2→CuNH3+NH3 is determined to be 11(3) kcal mol-1 through a thermodynamic relationship. [ABSTRACT FROM AUTHOR]

The ethylenediamine (en) complexes of Al, Ga, and In atoms were prepared in laser-vaporization supersonic molecular beams and studied with pulsed field ionization zero electron kinetic energy photoelectron spectroscopy and density functional theory. Several conformers of each metal complex are obtained by B3LYP calculations, and a five-membered cyclic structure is identified by combining the experimental measurements and theoretical calculations. Adiabatic ionization potentials, vibrational frequencies, and bond dissociation energies are determined for the ring structure. The ionization potentials of the Al, Ga, and In species are measured to be 32 784 (5), 33 324 (5), and 33 637 (7) cm-1, respectively, and metal-ligand dissociation energies of the ionic and neutral complexes are calculated to be 60.2/16.2 (Al+/Al), 55.5/13.0 (Ga+/Ga), and 50.0/11.4 (In+/In) kcal mol-1. Metal-ligand stretch and bend as well as a number of ligand-based vibrations are measured. Harmonic frequencies and anharmonicities of the M+-N (M=Al,Ga,In) stretch are determined for all three M+-en ions and the C-C-N bend of Ga+-en and In+-en. In comparison to monodentate methylamine, the bidentate binding of ethylenediamine leads to a significantly lower ionization potential and higher metal-ligand bond strength of the metal complexes. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The copper complexes were produced in pulsed laser vaporization molecular beams and investigated by pulsed-field ionization zero electron kinetic energy (ZEKE) spectroscopy and second-order Møller–Plesset (MP2) perturbation and hybrid B3LYP density functional theory calculations. The ground electronic states of Cu–X(CH[sub 3])[sub 3] and Cu[sup +]–X(CH[sub 3])[sub 3] (X=N,P,As) are [sup 2]A[sub 1] and [sup 1]A[sub 1], respectively, both with C[sub 3v] symmetry. From the ZEKE spectra, the adiabatic ionization potentials of the neutral molecules are determined to be 44 730, 41 508, and 42 324 cm-1, and the Cu[sup +]/Cu–X stretching frequencies are 268/199, 214/187, and 188/155 cm-1 for X=N, P, and As, respectively. The degenerate Cu[sup +]/Cu–P–C and Cu[sup +]/Cu–As–C bending frequencies are measured to be 146/83 and 118/52 cm-1, while the Cu[sup +]/Cu–N–C mode was not observed. In addition, the CH[sub 3] wag, X–C stretching, and XC[sub 3] umbrella modes are also measured for the phosphine and arsine complexes. From the MP2 theory, the dissociation energies of the Cu[sup +] and Cu complexes are estimated to be 59/12, 70/15, and 65/11 kcal mol-1 down the X group. Both MP2 and B3LYP predictions of ionic vibrational frequencies compare well with the spectroscopic values, but the B3LYP calculations of neutral low frequency modes are less satisfactory. On the other hand, the B3LYP calculations yield better ionization potentials than the MP2 methods for these molecules. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Aluminum–methylamine complexes are produced in pulsed molecular beams. Their electronic spectra are obtained using threshold photoionization and zero-electron-kinetic-energy photoelectron spectroscopies and interpreted using density functional and ab initio calculations. The photoelectron spectra reveal ground electronic states and intermolecular and ligand-based vibrations of Al–NH[sub n](CH[sub 3])[sub 3-n] and Al[sup +]–NH[sub n](CH[sub 3])[sub 3-n] (n=0–2), adiabatic ionization energies of Al–NH[sub n](CH[sub 3])[sub 3-n], and a low-lying excited electronic state of Al–NH[sub 2]CH[sub 3]. In addition, the spectroscopic measurements and theoretical calculations show strong methyl substitution effects on the ionization energies and metal–ligand binding. Striking spectral differences are discovered between these aluminum complexes and previously studied gallium and indium analogues. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The yttrium complexes with one and two dimethyl ethers and their deuterated derivatives are prepared with laser vaporization molecular beam techniques, identified with photoionization time-of-flight mass spectrometry, and investigated with pulsed-field-ionization zero-electronkinetic-energy (ZEKE) photoelectron spectroscopy and ab initio calculations. Adiabatic ionization potentials and yttrium-oxygen stretch and ether-based vibrations are measured for the 1:1 and 1:2 complexes. Fermi interactions are observed from the ZEKE spectra of the 1:1 species. The ground electronic states of the monoligand complexes are determined to be [SUP2]A[SUB2] for the neutral and [SUP1]A[SUB1] for the singly charged positive ion, both in C[SUB2v] symmetry, with yttrium binding to oxygen. The coordination of a second ether forms a diligand complex with a linear oxygen-yttrium-oxygen configuration. This is the first electronic-vibrational spectroscopic study of yttrium-polyatomic molecule complexes and weakly bound metal complexes with two or more polyatomic molecules. [ABSTRACT FROM AUTHOR]

Aluminum-trimethylphosphine and trimethylarsine have been prepared by pulsed laser vaporization. Their electronic spectra have been obtained for the first time, using pulsed field ionization zero electron kinetic energy (ZEKE) photoelectron spectroscopy. The ZEKE spectra reveal the information about adiabatic ionization energies, intermolecular and ligand vibrations, and charge effects on molecular geometries. In coordination with the experimental measurements, density functional theory has been used to calculate equilibrium geometries, vibrational frequencies, and bond dissociation energies for the neutral and ionic complexes. The calculations predict that ionization causes the most significant geometry changes in the Al–P–C or Al–As–C angles, in agreement with the experimental observations. The aluminum ion and atom bind phosphorus more strongly than arsenic in these species. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The gallium complexes were produced in pulsed molecular beams and studied with zero electron kinetic energy (ZEKE) photoelectron spectroscopy. Intermolecular vibrational frequencies and adiabatic ionization potentials (IPs) were obtained from ZEKE spectra. Ground electronic states were identified by combining the ZEKE spectra with quantum chemical and Franck–Condon calculations. Ga–NH[sub 3] has an IP of 40 135 cm-1 and metal-ligand stretching frequencies of 270 cm-1 (ω[sub s][sup +]) in the ion and 161 cm-1 (ν[sub s]) in the neutral. The IP of Ga–NH[sub 2]CH[sub 3] is 39 330 cm-1, and the vibrational frequencies are 93 cm-1 (ν[sub b]) for the Ga–N–C bending, 124 cm-1 (ω[sub b][sup +]) for the Ga[sup +]–N–C bending, and 299 cm-1 (ω[sub s][sup +]) for the Ga[sup +]–N stretching. The strength of the gallium–methylamine binding is stronger than that of the gallium–ammonia. The ground state of Ga–NH[sub 3] is [sup 2]A[sup ′](C[sub s]) and that of Ga[sup +]–NH[sub 3] is [sup 1]A[sub 1](C[sub 3v]). In contrast, Ga–NH[sub 2]CH[sub 3] has two doublets, [sup 2]A[sup ′] and [sup 2]A[sup ″](C[sub s]), with virtually the same energies, whereas Ga[sup +]–NH[sub 2]CH[sub 3] has a [sup 1]A[sup ′](C[sub s]) ground state. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

In order to study the laser plasma instabilities (LPIs) in the context of some novel six-side laser-driven indirect designs like the six-cylinder-port hohlraum and the three-axis cylindrical hohlraum, where the laser beams inject in hohlraum with a large angle. LPI experiments in cylindrical hohlraum with only outer beams were designed and performed based on the current laser arrangement condition of SGIII laser facility for the first time. Stimulated Brillouin backscatter (SBS) was found to be the dominant instability with high instantaneous reflectivity in experiments. A typical feature was obtained in the time-resolved spectra of SBS, which maintained similar for different laser intensities of the interaction beam. The experimental data are analyzed by the hydrodynamic simulations combined with HLIP code, which is based on the ray-tracing model. By analysis of experimental data, it is argued that the mixture of gas and Au in the region of their interface is important to SBS, which indicates the need for the mixture model between the filled gas and the high Z plasma from hohlraum wall in the hydrodynamic simulations. Nonlinear saturation of SBS as well as the smoothed beam are also discussed here. Our effective considerations of the ions pervasion effect and the smoothed beam provide utilitarian ways for improvement of the current ray-tracing method. [ABSTRACT FROM AUTHOR]

The technique of x-ray fluorescence imaging (XRFI) has been applied to the high-energy-density (HED) jet experiments on the SG-III prototype laser facility. The jet was produced by the interaction of the laser driven shock with the perturbed Ti disk. The fluorescence emission of the Ti ejecta was pumped by the V He-α emission and recorded using a Ross Pair Imager with an optimized configuration. We achieved a spatial resolution of 35 μm and a temporal resolution of 1 ns. We also developed a method to infer the density distribution of the jet from the fluorescence images and discussed the conditions under which this method was accurate. These experiments provided insight into the characteristics of a HED jet and implied that XRFI is a promising way for studying HED hydrodynamics. [ABSTRACT FROM AUTHOR]

The mass-selected infrared photodissociation (IRPD) spectroscopy was utilized to investigate the interactions of cationic cobalt with carbon dioxide molecules. Quantum chemical calculations were performed on the [Co(CO2)n]+ clusters to identify the structures of the low-lying isomers and to assign the observed spectral features. All the [Co(CO2)n]+ (n=2−6) clusters studied here show resonances near the CO2 asymmetric stretch of free CO2 molecule. Experimental and calculated results indicate that the CO2 molecules are weakly bound to the Co+ cations in an end-on configuration via a charge-quadrupole electrostatic interaction. The present IRPD spectra of [Co(CO2)n]+ clusters have been compared to those of Ar-tagged species ([Co(CO2)n]+-Ar), which would provide insights into the tagging effect of rare gas on the weakly-bounded clusters. [ABSTRACT FROM AUTHOR]

M-band flux asymmetry (MFA) may be another critical factor which can lead to low-mode distortion of implosion. We describe an experimental technique employing the x-ray fluorescence signature of material to investigate the MFA onto the capsule. Si was chosen to be the tracer layer since the inducing threshold for the K-shell fluorescence is much higher than soft x-ray but a little lower than M-band x-ray. The fluorescence images were recorded from a surrogate Si-coated ball, and thus, the P2 MFA was deduced from the fluorescence images. [ABSTRACT FROM AUTHOR]

The ultrafast dynamics of water molecules excited to the two F̃ states is studied by combining two-photon excitation and time-resolved photoelectron imaging techniques. The lifetimes of the F̃1A1 and F̃1B1 states of H2O (D2O) were derived to be 1.0±0.3 (1.9±0.4) and 10±3 (30±10) ps, respectively. We propose that the F̃1A1 state mainly decays through the D̃ state, due to the nonadiabatic coupling between them, while the F̃1B1 state decays through the F̃1A1 state via Coriolis interaction. [ABSTRACT FROM AUTHOR]

The integral cross sections and rate constants of pure rotational and ro-vibrational energy transfer processes for the Ar-HF system are thoroughly studied by using the time-independent close coupling method based on our newly constructed potential energy surface. Compared to previous theoretical results, pure rotational transitions in this work achieve better agreement with the experimental data. For ro-vibrational energy transfer, it is found that quasi-resonant transitions dominate the cross sections in all cases. Furthermore, the vibrational-resolved rate constant of transition v=1→v=0 increases very quickly with the temperature from 100 K to 1500 K and is also in good agreement with the available experimental results. [ABSTRACT FROM AUTHOR]

Vibrational frequencies of three niobium normal modes of triniobium dicarbide neutral and cation have been determined from pulsed field ionization-zero electron kinetic energy photoelectron spectra. The niobium stretching mode has a frequency of 326 cm[SUP-1]in the neutral and 339 cm[SUP-1]in the ion. The two deformation modes have frequencies of 238 and 82 cm[SUP-1]in the neutral and a degenerate frequency of 258 cm[SUP-1]in the ion. The geometry of the triniobium dicarbide has been established by comparing the experimental spectra with theoretical calculations. The cluster has a trigonal bipyramid geometry with carbon atoms capping on each face of the metal frame. The cation cluster has D[SUB3h] symmetry whereas the neutral cluster has lower symmetry resulting from a Jahn-Teller distortion. A second low-lying structure with doubly bridging carbon atoms has been identified by the calculations but has not yet been observed. [ABSTRACT FROM AUTHOR]

The geometrical structures of the ground states of triniobium monoxide, Nb3O, and its cation, Nb3O+, have been determined by an experimental and theoretical study. Vibrationally resolved photoelectron spectra of an Nb3O cluster beam were obtained at 100 and 300 K using the pulsed field ionization-zero electron kinetic energy technique. The spectra were simulated by calculating multidimensional Franck–Condon factors using the geometries and harmonic vibrational frequencies obtained from density functional theory for the minimum energy structures of the ion and neutral molecule. The rather remarkable agreement between the experiment and the simulated spectra establishes that Nb3O and Nb3O+ have planar C2v structures with the oxygen atom bridging two niobium atoms. These are the most complex transition metal cluster structures to date to be characterized by gas phase spectroscopic techniques. © 1995 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The technique of pulsed-field-ionization zero-kinetic-energy (PFI-ZEKE), photoelectron spectroscopy was employed to probe the electronic structure of the V+2 cation. Rotationally resolved PFI-ZEKE spectra of the V+2 ground state were obtained by two color excitation via the 700 nm A 3Πu←X 3Σ-g system. The observation of transitions from the A 3Π2u state to two spin–orbit components with Ω=1/2 and Ω=3/2, confirms that the cation ground state has 4Σg- symmetry, in accordance with previous experimental and theoretical work. Striking differences were observed in the rotational selection rules for the 4Σg-←A 3Π1u and the 4Σg-←A 3Π2u transitions. The adiabatic ionization potential of V2 was determined to be 51 271.14(50) cm-1. From an analysis of the rotational structure of the PFI-ZEKE spectra, the following molecular constants were determined for the 4Σg- state: r0=1.7347(24) Å, second order spin–orbit splitting, λ=5.248(17) cm-1, spin–rotation constant, γ=0.0097(87) cm-1, T0=51 282.20(50) cm-1 (1σ error bounds). © 1995 American Institute of Physics. [ABSTRACT FROM AUTHOR]

An ultraviolet Thomson-scattering system has been designed and implemented on the Shenguang-III laser facility, a 48-beam, 3ω (351 nm), 180 kJ-level laser driver for high energy density physics and inertial confinement fusion researches. The 4ω (263.3 nm) probe beam of the Thomson-scattering system is injected from the north pole (top) of the target chamber, with an assistant beam-pointing monitor to achieve high pointing accuracy. The Thomson-scattered light is collected by a double-Cassegrain optical transmission system, which provides an achromatic image over a wide wavelength range of 200–800 nm. A novel on-line alignment method is developed and applied to the diagnostic system, ensuring a volumetric positioning accuracy of ∼30 μm for the scattering volume. An online calibration is also conducted to provide the wavelength benchmark and the spectral resolution of the system. This Thomson-scattering system has been tested in a complicated experimental environment with gas-filled hohlraums, and a high-quality ion feature of the scattered light has been obtained. [ABSTRACT FROM AUTHOR]

Space-resolving flux detection is an important technique for the diagnostic of the radiation field within the hohlraum in inertial confinement fusion, especially for the radiation field diagnostic in the novel spherical hohlraum with octahedral six laser entrance holes (LEHs), where localized measurements are necessary for the discrimination of the radiation flux from different LEHs. A novel space-resolving flux detector (SRFD) is developed at the SG-III laser facility for the radiation flux measurement in the first campaign of the octahedral spherical hohlraum energetics experiment. The principle and configuration of the SRFD system is introduced. The radiation flux from the wall of a gas-filled octahedral spherical hohlraum is measured for the first time by placing the SRFD system at the equatorial position of the SG-III laser facility, aiming at the hohlraum wall through one of the six LEHs. The absolute radiation flux from the re-emission area on the hohlraum wall is measured, and good consistency is found between the experimental data and the calculated data from a three-dimensional view factor analysis. [ABSTRACT FROM AUTHOR]

A function that closely resembles the two-point time-domain Green's function (TDGF) representing the time delays associated with multipath between the two sensors can be recovered by correlating the noise field measured by two sensors. Here, a technique for extracting the TDGF from ambient ocean noise using acoustic vector sensors is presented. Experimental results suggest that the averaging time to extract TDGF is greatly reduced if sound pressure sensors (hydrophones) are replaced by acoustic vector sensors. The direct arrival and bottom bounce arrival were extracted successfully with only 1 min of vertical velocity data, while the bottom bounce arrival was not extracted with even 10 min of sound pressure data. [ABSTRACT FROM AUTHOR]

The local structure of La[SUB0.7]Ca[SUB0.3-x]Ba[SUBx]MnO[SUB3] (x = 0; 0.03; 0.06;...; and 0.3) lanthanum manganites were studied by extended x-ray absorption fine structure analysis. Dispersion, σ[SUP2][SUBMn-O], and asymmetry, σ[SUP3][SUBMn-O], of the pair distribution function for the Mn-O bond distances of MnO[SUB6] octahedron showed a maximum on x dependence. The maximum of σ[SUP2][SUBMn-O] is caused by an increase of dynamic displacements of the Mn-O bond distances near the Curie temperature, T[SUBC]. The observed x dependence of σ[SUP3][SUBMn-O] is caused by a reduction in mobility of the charge carriers approaching T[SUBC] from low as well as high temperatures. [ABSTRACT FROM AUTHOR]

We demonstrate optical far-field super-resolution microscopy using an array of nitrogen vacancy centers in bulk diamond as near-field optical probes. The local optical field, which transmits through the nanostructures on the diamond surface, is measured by detecting the charge state conversion of the nitrogen vacancy center. Locating the nitrogen vacancy center with a spatial resolution of 6.1 nm is realized with charge state depletion nanoscopy. The nanostructures on the surface of a diamond are then imaged with a resolution below the optical diffraction limit. The results offer an approach to build a general-purpose optical super-resolution microscopy technique and a convenient platform for high spatial resolution quantum sensing with nitrogen vacancy centers. [ABSTRACT FROM AUTHOR]

La atom reactions with 1-butene, 2-butene, and isobutene are carried out in a laser-vaporization molecular beam source. The three reactions yield the same La-hydrocarbon products from the dehydrogenation and carbon-carbon bond cleavage and coupling of the butenes. The dehydrogenated species La(C4H6) is the major product, which is characterized with mass-analyzed threshold ionization (MATI) spectroscopy and quantum chemical computations. The MATI spectrum of La(C4H6) produced from the La+1-butene reaction exhibits two band systems, whereas the MATI spectra produced from the La+2-butene and isobutene reactions display only a single band system. Each of these spectra shows a strong origin band and several vibrational progressions. The two band systems from the spectrum of the 1-butene reaction are assigned to the ionization of two isomers: La[C(CH2)3] (Iso A) and La(CH2CHCHCH2) (Iso B), and the single band system from the spectra of the 2-butene and isobutene reactions is attributed to Iso B and Iso A, respectively. The ground electronic states are 2A1 (C3v) for Iso A and 2A′ (Cs) for Iso B. The ionization of the doublet state of each isomer removes a La 6s-based electron and leads to the 1A1 ion of Iso A and the 1A′ ion of Iso B. The formation of both isomers consists of La addition to the C=C double bond, La insertion into two C(sp3)—H bonds, and H2 elimination. In addition to these steps, the formation of Iso A from the La+1-butene reaction may involve the isomerization of 1-butene to isobutene prior to the C—H bond activation, whereas the formation of Iso B from the La+trans-2-butene reaction may include the trans- to cis-butene isomerization after the C—H bond activation. [ABSTRACT FROM AUTHOR]

Detailed research on the interaction of a 0.53 μm laser pulse with millimeter-scale plasmas produced by a gasbag target on the Shengguang-II facility is presented. The x-ray pinhole images confirm that millimeter-scale plasmas are generated and the x-ray framing images show a temporal window of 0.6-1.1 ns during which the millimeter-scale plasmas exist. The electron temperature is measured with a collective Thomson scattering system, providing 0.64 keV for C5H12 and 1.8 keV for Xe plasmas. The electron density is inferred from the stimulated Raman scattering spectra. The experimental spectra show large differences for C5H12- and Xe-filled gasbags. A one-dimensional code based upon steady-state, kinetic linear theory is applied to calculate the stimulated Raman scattering spectra. Excellent agreement between the calculated and experimental results shows that the plasma parameters, especially the electron density and the temperature, dominate the disruption behavior of stimulated Raman scattering. The results also indicate that stimulated Raman scattering is probably located within specific region of the gasbag. The time-integrated reflectivity of both the stimulated Raman and Brillouin scattering is at a low level, even in the conditions of high laser intensity (1.5×1015 W/cm2) and no beam-smoothing. The experimental results are promising for future ignition experiments with a 0.53 μm laser as the driver. [ABSTRACT FROM AUTHOR]

Streak camera is widely used in continuous time diagnostics in fast physical process. To produce accurate result, it requires delicate calibration and a reliable analysis method. High quality sweep-rate data with uncertainty smaller than 0.5% are obtained over the full record area by a constrained fitting method of peak position measurement, with a short pulse laser and an etalon as the fiducial source. The temporal response is linearized by this full-screen sweep-rate data, which eliminates errors in measurement due to nonlinearity and space-distortion inherent in streak camera. [ABSTRACT FROM AUTHOR]

The Hohlraum physics experiments performed on the SGIII-prototype laser facility are simulated by using our two-dimensional radiation hydrodynamic code LARED-H, and the influence of laser intensity on the two-dimensional Hohlraum simulations is studied. Both the temporal radiation temperature and the x-ray spectrum from the simulations agree well with the observations, except that the simulated M-band fraction (greater than 2 keV) is obviously smaller than the observation. According to our study, the coupling efficiency from laser to x-ray is around 70% for SGIII-prototype laser facility Hohlraums. [ABSTRACT FROM AUTHOR]

Cerium, praseodymium, and neodymium complexes of 1,3,5,7-cyclooctatetraene (COT) complexes were produced in a laser-vaporization metal cluster source and studied by pulsed-field ionization zero electron kinetic energy spectroscopy and quantum chemical calculations. The computations included the second-order Mo\ller-Plesset perturbation theory, the coupled cluster method with single, double, and perturbative triple excitations, and the state-average complete active space self-consistent field method. The spectrum of each complex exhibits multiple band systems and is assigned to ionization of several low-energy electronic states of the neutral complex. This observation is different from previous studies of M(COT) (M = Sc, Y, La, and Gd), for which a single band system was observed. The presence of the multiple low-energy electronic states is caused by the splitting of the partially filled lanthanide 4f orbitals in the ligand field, and the number of the low-energy states increases rapidly with increasing number of the metal 4f electrons. On the other hand, the 4f electrons have a small effect on the geometries and vibrational frequencies of these lanthanide complexes. [ABSTRACT FROM AUTHOR]

This note describes multi-updates of the novel flat-response x-ray detector in fabrication technology, experimental application, and data uncertainty evaluation. Unlike the previous design, the compound filter is combined into one piece through an improved fabrication process that greatly enhanced its self-supporting capability. A method of pinhole-array imaging is introduced into the experimental application process to stop any debris from the hohlraum and to uniformly reduce the radiation flux. The experimental results show that this method works well. Furthermore, a method of uncertainty evaluation of the radiation flux measurement by the novel flat-response x-ray detector has been developed. The influence of the radiation spectrum to the flux measurement is analyzed. The evaluation shows that the relative uncertainty of the radiation flux is about 10% in higher radiation temperature condition (Tr > 150 eV) and 16% in lower radiation temperature condition (Tr < 100 eV). [ABSTRACT FROM AUTHOR]

By inserting a layer of (dibenzoylmethanato)3-(bathophenanthroline)-ytterbium (Yb–C) between copper phthalocyanine (CuPc) emitting layer and electron transport layer, intense and broadband electroluminescence (EL) were achieved at 930–1300 nm spectral region in a phosphorescent EL device. The intensity and bandwidth are increased by about 50 and 4 times, respectively, compared with the EL device without Yb–C layer. The improvement in the EL intensity and band broadening were attributed to the energy transfer from Yb–C to CuPc and the overlapping of the Yb3+ near-infrared emission band with the CuPc emission band. [ABSTRACT FROM AUTHOR]

Precise fabrication of three-dimensional (3D) self-standing microstructures on thin glass plates via two-photon induced polymerization (TPP) has been an important issue for innovative 3D nanodevices and microdevices. However, there are still issues remaining to be solved, such as building 3D microstructures on opaque materials via TPP and being able to implant them as functional parts onto practical systems. To settle these issues simply and effectively, the authors propose a contact print lithography (CPL) method using an ultraviolet-curable polymer layer. They report some of the possibilities and potential of CPL by presenting their results for transplanting 3D microstructures onto large-area substrates and also their examination of some of the effects of the process parameters on CPL. [ABSTRACT FROM AUTHOR]

Ultraprecise fabrication of three-dimensional (3D) microstructures comes up to be one of the most important issues in two-photon induced photopolymerization. To date, it has been difficult to fabricate 3D microstructures without any deformation due to the surface tension between a rinsing material and solidified microstructures during the developing process: In general, the surface tension significantly affects the precision of the resulting 3D microstructures. To overcome this problem, the authors propose a simple and effective laser scanning method to reinforce the strength of 3D microstructures without loss of precision. Overall, a complex 3D artistic sculpture such as “The Thinker” was reproduced in the controlled ultraprecise form, which shows that the proposed method enables the fabrication of 3D patterns with dramatically improved precision and stability. [ABSTRACT FROM AUTHOR]

Ultraprecise fabrication of three-dimensional (3D) microstructures comes up to be one of the most important issues in two-photon induced photopolymerization. To date, it has been difficult to fabricate 3D microstructures without any deformation due to the surface tension between a rinsing material and solidified microstructures during the developing process: In general, the surface tension significantly affects the precision of the resulting 3D microstructures. To overcome this problem, the authors propose a simple and effective laser scanning method to reinforce the strength of 3D microstructures without loss of precision. Overall, a complex 3D artistic sculpture such as “The Thinker” was reproduced in the controlled ultraprecise form, which shows that the proposed method enables the fabrication of 3D patterns with dramatically improved precision and stability. [ABSTRACT FROM AUTHOR]

LaO2 was produced in a pulsed laser-vaporization molecular beam source and studied by mass-analyzed threshold ionization (MATI) spectroscopy and ab initio electronic structure calculations. The calculations included density functional theory, second-order perturbation theory, coupled cluster theory, and complete active space self-consistent field methods. The adiabatic ionization energy of the molecule and vibrational frequencies of the molecule and its cation were measured accurately for the first time from the MATI spectrum. Numerous ionization processes of lanthanum dioxide, peroxide, and superoxide were considered; the 3B2 ← 4B2 electronic transition of the dioxide was assigned upon comparison with the observed spectrum. The ionization energy and O-La-O bending frequency of the 4B2 neutral state are 4.9760 (6) eV and 92 cm-1, respectively. The La-O stretching and O-La-O bending frequencies of the 3B2 cationic state are 656 and 122 cm-1, respectively. The 4B2 state is formed by two electron transfer from lanthanum to oxygen atoms, and the 3B2 state is produced by the further removal of a lanthanum 6s-based electron. [ABSTRACT FROM AUTHOR]

Monobenzene complexes of yttrium (Y), lanthanum (La), and lutetium (Lu), M(C6H6) (M = Y, La, and Lu), were prepared in a laser-vaporization supersonic molecular beam source and studied by pulsed-field ionization zero electron kinetic energy (ZEKE) spectroscopy and ab initio calculations. The calculations included the second-order perturbation, the coupled cluster with single, double, and perturbative triple excitation, and the complete active space self-consistent field methods. Adiabatic ionization energies and metal-benzene stretching frequencies of these complexes were measured for the first time from the ZEKE spectra. Electronic states of the neutral and ion complexes and benzene ring deformation were determined by combining the spectroscopic measurements with the theoretical calculations. The ionization energies of M(C6H6) are 5.0908 (6), 4.5651 (6), and 5.5106 (6) eV, and the metal-ligand stretching frequencies of [M(C6H6)]+ are 328, 295, and 270 cm-1 for M = Y, La, and Lu, respectively. The ground states of M(C6H6) and [M(C6H6)]+ are 2A1 and 1A1, respectively, and their molecular structures are in C2v point group with a bent benzene ring. The deformation of the benzene ring upon metal coordination is caused by the pseudo Jahn-Teller interaction of (12E2+12A1+22E2) x e2 at C6v symmetry. In addition, the study shows that spectroscopic behaviors of Y(C6H6) and La(C6H6) are similar to each other, but different from that of Lu(C6H6). [ABSTRACT FROM AUTHOR]

Single-photon pulsed field ionization-zero electron kinetic energy photoelectron spectroscopy has been used to study the indium–methylamine complexes. The photoelectron spectra have been assigned using density functional theory and Franck–Condon calculations. The spectral assignments identify the symmetric In[sup +]–N stretch mode for In[sup +]–NH[sub 2]CH[sub 3] (259 cm-1), In[sup +]–NH(CH[sub 3])[sub 2] (200 cm-1), and In[sup +]–N(CH[sub 3])[sub 3] (158 cm-1); In–N stretch for In–N(CH[sub 3])[sub 3] (110 cm-1); In[sup +]–N–C bend for In[sup +]–NH[sub 2]CH[sub 3] (110 cm-1) and In[sup +]–NH(CH[sub 3])[sub 2] (120 cm-1); In–N–C bend for In–NH[sub 2]CH[sub 3] (91 cm-1) and In–NH(CH[sub 3])[sub 2] (106 cm-1); and In[sup +]–N–H bend for In[sup +]–NH(CH[sub 3])[sub 2] (324 cm-1). Methyl substitutions for hydrogen atoms greatly influence the indium–nitrogen stretch forces and ionization potentials of the complexes. The indium–amine binding in these complexes includes orbital interaction and electrostatic forces. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The cylindrical vacuum hohlraum energy at the SGIII laser facility [X. T. He and W. Y. Zhang, Eur. Phys. J. D 44, 227 (2007) and W. Zheng et al., High Power Laser Sci. Eng. 4, e21 (2016)] is investigated for the first time. The hohlraum size and the laser energy are intermediate between the Nova and NIF typical hohlraum experiments. It is found that the SGIII hohlraum exhibits an x-ray conversion efficiency of about 85%, which is more close to that of the NIF hohlraum. The LARED simulations of the SGIII hohlraum underestimate about 15% of the radiation flux measured from the laser entrance hole, while the capsule radiation drive inferred from the x-ray bangtime is roughly consistent with the experiments. The underestimation of the SGIII hohlraum radiation flux is mainly caused by the more enclosed laser entrance hole in the LARED simulation. The comparison between the SGIII and NIF hohlraum simulations by LARED indicates that the LARED generally underestimates the measured radiation flux by 15% for the high x-ray conversion efficiency hohlraums, while it can roughly predict the capsule radiation drive inside the hohlraum. [ABSTRACT FROM AUTHOR]

A coil-unit barrel for a helical coil electromagnetic launcher is described. It provides better features of high structural strength and flexible adjustability. It is convenient to replace the damaged coil units and easy to adjust the number of turns in the stator coils due to the modular design. In our experiments, the highest velocity measured for a 4.5-kg projectile is 47.3 m/s and the mechanical reinforcement of the launcher could bear 35 kA peak current. The relationship between the energy conversion efficiency and the inductance gradient of the launcher is also studied. In the region of low inductance gradient, the efficiency is positively correlated with the inductance gradient. However, in the region of high inductance gradient, the inter-turn arc erosion becomes a major problem of limiting the efficiency and velocity of the launcher. This modular barrel allows further studies in the inter-turn arc and the variable inductance gradient helical coil launcher. [ABSTRACT FROM AUTHOR]

In laser driven hohlraums, laser beams on the same incident cone may have different beam and plasma conditions, causing beam-to-beam backscatter difference and subsequent azimuthal variations in the x-ray drive on the capsule. To elucidate the large variation of backscatter proportion from beam to beam in some gas-filled hohlraum shots on Shenguang-III, two 28.5° beams have been measured with the Stimulated Raman Scattering (SRS) time-resolved spectra. A bifurcated fiber is used to sample two beams and then coupled to a spectrometer and streak camera combination to reduce the cost. The SRS spectra, characterized by a broad wavelength, were further corrected considering the temporal distortion and intensity modulation caused by components along the light path. This measurement will improve the understanding of the beam propagation inside the hohlraum and related laser plasma instabilities. [ABSTRACT FROM AUTHOR]

Thermal annealing dependent performance was demonstrated in poly(3-hexyl-thiophene):phenyl-C61-butyric acid methyl ester based organic photovoltaics with anionic conjugated polyelectrolyte (PFEOSO3Na) as the cathode interface layer. The best performance can be achieved when the device based PFEOSO3Na was treated by post-annealing, exhibiting about 20% higher power conversion efficiency than the control device. Atomic force microscopy studies showed that the morphology of interface layers changed under different device treatment processes, leading to various electron extraction efficiencies. Compared with different interface materials, it further demonstrated the best charge extraction efficiency in the device with PFEOSO3Na layer, due to its stronger interface dipole. [ABSTRACT FROM AUTHOR]

Although it plays a critical role in the photophysics and catalysis of lanthanides, spin-orbit coupling of electrons on individual lanthanide atoms in small clusters is not well understood. The major objective of this work is to probe such coupling of the praseodymium (Pr) 4f and 6s electrons in Pr2O2 and Pr2O2+. The approach combines mass-analyzed threshold ionization spectroscopy and spin-orbit multiconfiguration second-order quasi-degenerate perturbation theory. The energies of six ionization transitions are precisely measured; the adiabatic ionization energy of the neutral cluster is 38 045 (5) cm-1. Most of the electronic states involved in these transitions are identified as spin-orbit coupled states consisting of two or more electron spins. The electron configurations of these states are 4f46s2 for the neutral cluster and 4f46s for the singly charged cation, both in planar rhombus-type structures. The spin-orbit splitting due to the coupling of the electrons on the separate Pr atoms is on the order of hundreds of wavenumbers., (© 2023 Author(s). Published under an exclusive license by AIP Publishing.)

The precise ionization energy of praseodymium oxide (PrO) seeded in supersonic molecular beams is measured with mass-analyzed threshold ionization (MATI) spectroscopy. A total of 33 spin-orbit (SO) states of PrO and 23 SO states of PrO + are predicted by second-order multiconfigurational quasi-degenerate perturbation (MCQDPT2) theory. Electronic transitions from four low-energy SO levels of the neutral molecule to the ground state of the singly charged cation are identified by combining the MATI spectroscopic measurements with the MCQDPT2 calculations. The precise ionization energy is used to reassess the ionization energies and the reaction enthalpies of the Pr + O → PrO + + e - chemi-ionization reaction reported in the literature. An empirical formula that uses atomic electronic parameters is proposed to predict the ionization energies of lanthanide monoxides, and the empirical calculations match well with available precise experimental measurements.

The structural and bonding properties of the Pt 2 C 2n - (n = 1-3) complexes have been investigated by mass-selected photoelectron velocity-map imaging spectroscopy with quantum chemical calculations. The adiabatic detachment energies and vertical detachment energies of Pt 2 C 2n - have been obtained from the measured photoelectron imaging spectra. Theoretical results indicate that the lowest-energy isomers of Pt 2 C 2n - (n = 1-3) possess linear chain-shaped configurations. The binding motif in the most stable isomer of Pt 2 C 2 - has a linear cumulenic structure with a Pt=C=C=Pt configuration, and the structural characteristic persists up to all the lowest-energy isomers of the Pt 2 C 4 - and Pt 2 C 6 - anions. The chemical bonding analyses indicate that the Pt 2 C 2n - (n = 1-3) complexes have multicenter two-electron characteristics.

Upconverting nanoparticles (UCNPs) composed of NaYF 4 and doped with photoactive Yb 3+ and Er 3+ (NaYF 4 :Yb/Er) are highly desirable for many biological applications, but obtaining stable dispersions of UCNPs is challenging. Traditional synthetic methods often use complicated synthetic steps, produce toxic side products, and require post modifications to make UCNPs more dispersible in aqueous solutions. In this study, we demonstrate that laser ablation in liquid (LAL) is a novel approach to synthesize water-dispersible and -stable UCNPs with advantages of particle-size tuning, in situ coating of UCNPs with capping agents, no use of toxic or high boiling point solvents, and short reaction times. NaYF 4 :Yb/Er UCNPs were produced through LAL of annealed targets using water as the liquid, and their compositions and properties were investigated at a laser fluence of 0.57 J cm -2 -6.22 J cm -2 by direct capping with citric acid and ethylene glycol and by comparing with the UCNPs prepared from the traditional hydrothermal method. Low laser fluences produced polydisperse particles consisting of no photoactive species through a thermal evaporation mechanism, while high laser fluences generated UCNPs with more uniform morphologies and compositions similar to the target material by an explosive ejection mechanism. The inclusion of capping agents during LAL allowed for direct coating of the UCNP surface without the need of post modifications, and the concentrations of capping agents affected the UCNP photoluminescence lifetimes. As compared to the hydrothermal method, the LAL-prepared samples showed better size control and no degradation of the capping agents.