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By employing the two-color infrared (IR)-vacuum ultraviolet (VUV) laser photoionization (PI) schemes, we have determined the C[Single_Bond]H stretching frequencies ν[sub 12]=3097.7 cm[sup -1] for trichloroethene (CHCl==CCl[sub 2]) and ν[sub 12][sup +]=3066 cm[sup -1] for CHCl==CCl[sub 2][sup +]. On the basis of the IR-VUV-pulsed field ionization-photoelectron (PFI-PE) measurement, the ratio of the state-to-state PI cross section for CHCl==CCl[sub 2][sup +](ν[sub 12][sup +]=1)←CHCl==CCl[sub 2](ν[sub 12]=1) to that for the formation of the ground state ion from the ground state neutral is determined to be 0.24. The VUV-PI efficiency (PIE) spectrum for CHCl==CCl[sub 2] and IR-VUV-PIE spectrum for CHCl==CCl[sub 2](ν[sub 12]=1) show that the state-to-state PI cross section for the formation of CHCl==CCl[sub 2][sup +] in the ground state from CHCl==CCl[sub 2](ν[sub 12]=1) is ≈0.006 that from CHCl==CCl[sub 2] in its ground state. As expected, the IR-VUV-PIE onset for CHCl==CCl[sub 2](ν[sub 12]=1) exhibits less hot-band tailing than the VUV-PIE onset for supersonically cooled CHCl==CCl[sub 2]. After taking into account the ν[sub 12] frequency, the ionization energy values for CHCl==CCl[sub 2] determined based on the IR-VUV-PIE and VUV-PFI-PE measurements are found to be in excellent agreement. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

The single-photon pulsed field ionization photoelectron (PFI-PE) spectrum of trans-2-butene (trans-CH[sub 3]CH=CHCH[sub 3]) in the energy range of 73 500–75 850 cm-1 has been measured using vacuum ultraviolet laser sources. The semi-empirical simulation of fine structures resolved in the original PFI-PE band yields a value of 73 624.7±2.0 cm[sup -1] for the ionization energy (IE) of trans-2-butene. The vibrational bands for trans-CH[sub 3]CH=CHCH[sub 3][sup +] resolved in the PFI-PE spectrum are assigned based on ab initio calculations of the vibrational frequencies and Franck-Condon factors (FCFs) for ionization transitions. This assignment has provided reliable vibrational frequencies (ν[sub 1][sup +]=104 cm[sup -1], ν[sub 2][sup +]=127 cm[sup -1], ν[sub 3][sup +]=131 cm[sup -1], ν[sub 5][sup +]=484 cm[sup -1], ν[sub 8][sup +]=798 cm[sup -1], ν[sub 13][sup +]=1164 cm[sup -1], ν[sub 14][sup +]=1264 cm[sup -1], ν[sub 16][sup +]=1307 cm[sup -1], ν[sub 20][sup +]=1407 cm[sup -1], and ν[sub 22][sup +]=1567 cm[sup -1]) for trans-CH[sub 3]CH=CHCH[sub 3][sup +]. The PFI-PE spectrum is compared to the recently reported PFI-photoion (PFI-PI) spectrum for trans-2-butene. The major difference observed between the PFI-PE and PFI-PI spectra is that the intensities for excited vibrational bands were significantly suppressed or indiscernible in the PFI-PI spectrum, suggesting that the lifetimes for high-n Rydberg states associated with these excited vibrational bands were greatly reduced under the conditions used in the PFI-PI study. The experimental conditions used in the PFI-PI study also led to an IE value of about 20 cm-1 lower than that obtained in the PFI-PE measurement. We have also reassigned the vibrational bands resolved in the PFI-PE spectrum for cis-2-butene based on the FCF calculation and a more reliable set of theoretical vibrational frequencies. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Reports that rotationally resolved pulsed field ionization photoelectron (PFI-PE) spectra have been obtained for oxygen in the energy range of 12.05-18.15 eV. Relative vibrational band intensities for O[sup +][sub 2]; Spectral simulation and assignment of rotational branches.

Reports on the acquisition of rotationally resolved pulsed field ionization photoelectron spectra of oxygen covering the ionization transitions of O[sup +][sub 2](B [sup 2]Sigma[sup -][sub g], v[sup +]=0-7,N[sup +]...O[sub 2](X [sup 3]Sigma[sup -][sub g], v''=0,N''). Pulsed field ionization photoelectron measurements; Measurements of lifetimes for high-n Rydberg states.

Using two-colour visible (Vis)–ultraviolet (UV) photoionisation and pulsed field ionisation–photoelectron (PFI–PE) methods, we have obtained cleanly rotationally resolved photoelectron spectra for ZrO+(X2Δ3/2,5/2; v+= 0, 1, and 2). The rotation assignment of these state-to-state Vis–UV–PFI–PE spectra has allowed the unambiguous determination of the ground state term symmetry for ZrO+(X) to be2Δ3/2, and the adiabatic ionisation energy of90Zr16O, IE(90Zr16O) = 54,948.3(8) cm−1[6.81272(10) eV]. The symmetry of the ionic ZrO+(X2Δ3/2) ground state determined here disagrees with that reported in previous experiments. The rotational and vibrational constants determined in this experiment for the ionic90Zr16O+(X2Δ3/2) ground state are:Be+= 0.4343(8) cm−1and αe+= 0.0019(5) cm−1, and ωe+= 991.2(8) cm−1and ωe+xe+= 3.5(8) cm−1; and those for the ionic90Zr16O+(X2Δ5/2) excited spin-orbit state are:Be+= 0.4357(6) cm−1and αe+= 0.0022(4) cm−1, and ωe+= 991.9(8) cm−1and ωe+xe+= 3.6(8) cm−1, respectively. Based on the latterBe+value, the equilibrium bond distances are determined to bere+= 1.691(2) Å for90Zr16O+(X2Δ3/2) andre+= 1.688(1) Å for90Zr16O+(X2Δ5/2). The IE(ZrO) along with the spectroscopic constants obtained here are valuable for benchmarking theab initioquantum chemical calculations for energetic and structural predictions of ZrO/ZrO+. [ABSTRACT FROM AUTHOR]

Focuses on high resolution threshold and pulsed field ionization photoelectron spectroscopy using multi-bunch synchrotron radiation. Resolution for threshold photoelectron measurements; Characteristics of the monochromatized vacuum ultraviolet beam at the chemical dynamics beamline; Photoionization-photoelectron apparatus.

We have obtained rotationally resolved pulsed-field ionization photoelectron (PFI-PE) spectra for O[sub 2] in the energy range of 17.05-18.13 eV, covering the ionization transitions O[sub 2][sup +](A [sup 2]Π[sub u],v[sup +]=0-12,N[sup +])←O[sub 2](X [sup 3]Σ[sub g][sup -],v[sup ″]=0,N[sup ″]). Although these O[sub 2][sup +](A [sup 2]Π[sub u],v[sup +]) PFI-PE bands have significant overlaps with vibrational bands for O[sub 2][sup +](a [sup 4]Π[sub u]) and O[sub 2][sup +](X [sup 2]Π[sub g]), we have identified all the O[sub 2][sup +](A [sup 2]Π[sub u],v[sup +]=0-12) bands by simulation of spectra obtained using supersonically cooled O[sub 2] samples with rotational temperatures approx. 20 and 220 K. While these v[sup +]=0-12 PFI-PE bands represent the first rotationally resolved photoelectron data for O[sub 2][sup +](A [sup 2]Π[sub u]), the PFI-PE bands for O[sub 2][sup +](A [sup 2]Π[sub u],v[sup +]=9 and 10) are the first rotationally resolved spectroscopic data for these levels. The simulation also allows the determination of accurate ionization energies, vibrational constants, and rotational constants for O[sub 2][sup +](A [sup 2]Π[sub u],v[sup +]=0-12). The analysis of the PFI-PE spectra supports the conclusion of the previous emission study that the O[sub 2][sup +](A [sup 2]Π[sub u],v[sup +]=9 and 10) states are strongly perturbed by a nearby electronic state. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We have obtained rotationally resolved pulsed field ionization-photoelectron (PFI-PE) spectra of O[sub 2] in the energy range of 16.0-18.0 eV, covering ionization transitions O[sub 2][sup +](a [sup 4]Π[sub u], v[sup +]=0-18,J[sup +])←O[sub 2](X [sup 3]Σ[sub g][sup .], v[sup ″]=0,N[sup ″]). Although these vibrational PFI-PE bands for O[sub 2][sup +](a [sup 4]Π[sub u], v[sup +]) have significant overlaps with those for O[sub 2][sup +](X [sup 2]Π[sub g]) and O[sub 2][sup +](A [sup 2]Π[sub u]), we have identified all O[sub 2][sup +](a [sup 4]Π[sub u], v[sup +]=0-18) bands by simulation of spectra obtained using supersonically cooled O[sub 2] samples with rotational temperatures approx. 20 and 220 K. While the v[sup +]=4-18PFI-PE bands represent the first rotationally resolved photoelectron data for O[sub 2][sup +](a [sup 4]Π[sub u]), the PFI-PE bands for O[sub 2][sup +](a [sup 4]Π[sub u], v[sup +]=10-18) are the first rotationally resolved spectroscopic data for these levels. The simulation also allows the determination of accurate ionization energies, vibrational constants, and rotational constants for O[sub 2][sup +](a [sup 2]Π[sub u], v[sup +]=0-18). The observed intensities of spin-orbit components for the majority of O[sub 2][sup +](a [sup 2]Π[sub u], v[sup +]) vibrational bands are in accordance with the forced spin-orbit/rotational autoionization mechanism. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Abstract: The comparison of rotationally resolved infrared–vacuum ultraviolet–pulsed field ionization–photoelectron (IR–VUV–PFI–PE) depletion and IR–VUV–photoion measurements of C2H4 has illustrated the difference of these two methods and the rotational nature of the IR–VUV–PFI–PE depletion method. The IR–VUV–photoion spectra of trans-2-butene in the region 2910–3000cm−1 observed at different delays between the IR and VUV lasers are also presented to show that the IR–VUV–PI method is potentially useful for the study of intramolecular vibrational redistributions (IVRs). For short IVR lifetimes of vibrationally excited polyatomic neutrals, the IR–VUV–PFI–PE depletion method can serve as an alternative of the IR–VUV–PI scheme for rotationally resolved IR spectroscopy measurements. [Copyright &y& Elsevier]