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Photodissociation spectroscopy of mono‐hydrated aniline dimer (An2W+) cation was performed to determine its most stable structure and the charge resonance (CR) interaction therein. In its photodissociation action spectrum, two local excitation (LE) bands at ∼1.9 eV (656 nm) and >3.0 eV (<420 nm), previously assigned to A2A~2 ← X2B~1 and B2B~1 ← X2B~1 transition, respectively, for aniline dimer (An2+), were also observed for An2W+. On the other hand, the absorption band at ∼1.12 eV (1110 nm) from the CR interaction reported for An2+ disappeared in case of An2W+. Based on this infrared photodissociation action spectra supported by quantum chemical calculations, we suggest that the most stable structure of An2W+ maintains the stacked structure of An2+ but H2O molecule connected to the amino group of aniline molecule via hydrogen bonding plays a role to suppress the CR interaction. [ABSTRACT FROM AUTHOR]

Photofragmentation of mass-selected aniline+(water)n (An+Wn, n=4–20) clusters is investigated over photon energies ranging from 1.65 to 4.66 eV by linear tandem time-of-flight mass spectrometry. The aniline ring turns out to survive irradiation of photons, and most of the absorbed photon energy flows to the hydrogen-bonding networks to be used up for liberation of water molecules. The average number of ejected water molecules measured as a function of photon energy reveals that the loss of water molecules is a photoevaporation process. The distributions of internal energies for parent ions and binding energies of water molecules are estimated from the plots of photofragment branching ratio versus photon energy, which give nice Gaussian fits. Also, density functional theory calculations are performed to obtain optimized structures of isomers for An+Wn clusters and binding energies. The authors find that the An+W6 cluster has a highly symmetric structure and its binding energy in An+W6→An+W5+W stands out. This is in line with the experimental results showing that n=6 is a magic number in the mass distribution and An+W6 is relatively stable in metastable decay. [ABSTRACT FROM AUTHOR]

The article presents study on power-dependent photocatalytic activity of zinc oxide (ZnO). It mentions photocatalytic activity of ZnO investigated using laser pulses for dye molecule rhodamine 101. It adds emission was collected using an optical lens, spectrally resolved using a monochromator, and detected using a photomultiplier.

Abstract: Infrared (IR) photodissociation spectra of aniline(H2O) n + (n =7–12) clusters in the region of 2800–3900cm−1 have been explicitly analyzed to elucidate their structures and structural strains in hydrogen bonding networks. Due to the potential barrier between anilide radical and hydrated water clusters (n =7–12), our experimental and theoretical results suggest that there is no proton-transferred structure in n =7–12 cluster. The spectroscopic results, combined with DFT calculations show a clear systematic change in hydrogen-bonded topology from a multiple-ring to a cage-like topology as their size increases from n =7 to 12. [Copyright &y& Elsevier]

Abstract: Photodissociation dynamics of hydrated aniline cluster cations, (n =1–10) was investigated in the infrared and UV–visible region focusing on the kinetic energy release (KER). In case of infrared photodissociation at 0.43eV, the KER was independent of the cluster size while it was clearly size-dependent at UV–visible energies. The excitation of different vibrational modes had no effect on the KER despite that the internal energies of the parent ions were different. The KER increased from 53 to 160meV for cluster with increase in the photon energy from 0.43 to 4.66eV. [Copyright &y& Elsevier]

Abstract: The infrared (IR) photodissociation of aniline–water–methanol cluster ion was investigated in the 2600–3900cm−1 region to examine the factors which play key roles in determining the branching ratio of a concurrent predissociation reaction. The dominant channel in the IR predissociation of AWM+ (A: aniline, W: water, M: methanol) was AWM+ →AM+ at all vibrational modes although the calculated binding energies of water and methanol were nearly the same. Also, the branching ratio was slightly dependent on the specific excited mode, ranging from 0.036 to 0.074; the most effective mode to kick out methanol was OH vibration of methanol. [ABSTRACT FROM AUTHOR]

Abstract: The potential energy surface (PES) for dissociation of aniline ion was determined using density functional theory molecular orbital calculations at the B3LYP/6-311+G(3df,2p)//B3LYP/6-31G(d) level. On the basis of the PES obtained, kinetic analysis was performed by Rice–Ramsperger–Kassel–Marcus (RRKM) calculations. The RRKM dissociation rate constants agreed well with previous experimental data. The most favorable channel was formation of the cyclopentadiene ion by loss of HNC, occurring through consecutive ring opening and re-closure to a five-membered ring. Loss of Hmpete with the HNC loss at high energy, which occurred by direct cleavage of an N–H bond or through ring expansion. [Copyright &y& Elsevier]

Molecular structures of aniline(pyrrole) + , aniline(ethanol) + , and aniline(benzene) + produced via resonance two-photon ionization at 266 nm were analyzed by infrared predissociation spectroscopy coupled with tandem mass spectrometry. Structural optimization and frequency calculation using density functional theory were carried out to suggest the most probable isomers which are in good agreement with the observed infrared absorption spectra. Intermolecular bonds in the cluster ions were formed such that the electronegative oxygen atom of the solvent molecule or the pi electron of the aromatic ring forms a hydrogen bonding to N H of aniline. [ABSTRACT FROM AUTHOR]

The molecular structures and predissociation dynamics of aniline (Phenylamine, PhNH 2 )-inert gas cluster cations PhNH 2 X + (X = Ne, Ar, and Kr) were investigated by infrared (IR) spectroscopy coupled with density functional theory (DFT) calculations and IR photofragmentation studies. The ring isomer was the minimum energy structure for PhNH 2 Ne + and PhNH 2 Ar + whereas the N H isomer was more stable in PhNH 2 Kr + . The decay constants of PhNH 2 X + for ejection of X excited with IR depended strongly on the structure of PhNH 2 X + , presumably because the rate of intramolecular vibrational energy redistribution (IVR) was governed by the structure. As a result, the dissociation was faster for the larger PhNH 2 X + clusters, because the rate of IVR was faster for the N H type structure than the ring type. The decay constants deviate from those expected from the Rice–Ramsperger–Kassel–Marcus (RRKM) theory calculation by the factors of 10 4 or larger, manifesting that the dissociation occurred mainly via nonstatistical pathways. [ABSTRACT FROM AUTHOR]

Vibrational predissociation dynamics of aniline(water) n + cluster ions formed via resonance two photon ionization followed by the absorption of single infrared photon was investigated. A linear tandem time of flight mass spectrometer designed for this research was tested by the dissociation of aniline + at 266 nm and observed decay constant matched well with the previous result. The rate of dissociation of aniline(water) n + cluster increased with internal energy, whereas decreased with increasing the size of cluster, manifesting that the intramolecular vibrational energy redistribution precedes VP. The internal energies of the cluster ions were estimated from comparing the experimental and Rice–Ramsperger–Kassel–Marcus calculation results. [ABSTRACT FROM AUTHOR]

Vibrational predissociation spectra of aniline(pyrrole)(water) 2 + and aniline(pyrrole)(water) 3 + clusters were taken at 2700–4000 cm −1 to verify their most stable structures. One N H of aniline was bonded to the π electron of pyrrole while the other N H was bonded to water. Pyrrole molecule was arranged in such a way that N H of pyrrole formed another hydrogen bond with a water molecule nearby. Water molecule was more easily ejected than pyrrole for both AnPyW 2 + and AnPyW 3 + although pyrrole had smaller binding energy than water. [ABSTRACT FROM AUTHOR]

The structures of [(aniline)-(methanol)-(water) 2 ]+ were investigated by infrared spectroscopy coupled with linear tandem mass spectrometry. We suggest the most stable structure of [(aniline)-(methanol)-(water) 2 ]+ through infrared photodissociation spectra supported by the density functional theory calculations at the level of ωB97X-D/cc-pVQZ. Methanol and one water molecule formed hydrogen bonding with the amino group of aniline, while the other water formed hydrogen bonding with methanol. Upon infrared excitation of [(aniline)-(methanol)-(water) 2 ]+, the water molecule connected to methanol turned out to be preferentially ejected, although the total internal energy in the cluster ion was large enough to dissociate other solvent molecules. This unique dissociation feature was attributed to the significant difference in the dissociation rates as obtained by the Rice-Ramsperger-Kassel-Marcus theory calculations as well as structural restriction. Unlabelled Image • The most stable structure of [(aniline)-(methanol)-(water) 2 ]+ was suggested by IR spectroscopy and DFT calculation. • One water molecule was ejected from [(aniline)-(methanol)-(water) 2 ]+ upon IR absorption. • The unique IR dissociation channel of [(aniline)-(methanol)-(water) 2 ]+ has been explained using RRKM theory. [ABSTRACT FROM AUTHOR]