Mass selected resonance enhanced multiphoton ionization spectroscopy of aniline–Arn (n=3,4,5, ...) van der Waals complexes

Abstract

Rydberg excited iodine-argon van der Waals complexes studied by resonance enhanced multiphoton ionization spectroscopy High resolution threshold photoelectron spectroscopy of aniline and aniline van der Waals complexes Suppression of fragment contributions to massselected resonance enhanced multiphoton ionization spectra of van der Waals clustersThe origin region of the SI +-So transitions of the aniline-Ar 3 , aniline-Ar 4 , and aniline-Ars molecules have been measured using mass selected resonance enhanced, multi photon ionization (REMPI) spectroscopy. The aniline-Ar 3 spectrum exhibits two distinct groups of peaks. The more prominent group displays a regular vibrational progression, with five obvious members and a spacing of ~ 16 cm -I. Vibrational structure in the other group is less distinctive. On the basis of cluster potential calculations described in this paper, we believe that two stable aniline-(argon) 3 isomers exist in the supersonic expansion and that the two groups of peaks correspond to absorption by these two isomers. Spectra recorded at masses corresponding to aniline-(argon)4 and aniline-(argon)s display broadened structure that probably reflects contributions from larger aniline-(argon) n clusters which fragment upon ionization. There is, however, some evidence for a progression with a spacing of ~ 16 cm -I in the aniline-(argon)4 spectrum. Dispersed fluorescence spectra from relatively small aniline-Ar n clusters (4 < n < 10) indicate that vibrational redistribution from Franck-Condon active van der Waals modes occurs with rates of at least 5 X 10'1 S -I.

Resonant two-photon two-color photoionization (R2P2CI) spectra of aniline-Ar n clusters: Isomer strutures and solvent shifts

“…Our Lennard-Jones parametrization of the An-Ar interaction is fairly standard and our choice of parameters is essentially the same as that of S. Leutwyler [6] with the parameters for the N-At interactions taken identical to those used by E.J. Bieske et al [ 16] (even within the point dipole approximation). Our treatment of the electrostatic contribution to the An-At potential is quite different from that of E.J.…”

“…Our treatment of the electrostatic contribution to the An-At potential is quite different from that of E.J. More importantly, we use the complete dipole tensor (2) to calculate the interaction (1); the scalar product form of the dipoleinduced dipole interaction ((3) of [ 16]) used by E.J. We place the molecular dipole at the center of charge (see Table 2) rather than on the carbon bonded to the nitrogen.…”

“…Bieske et al [16] have used a conceptually different technique to suppress spectral contamination due to fragmentation effects. Bieske et al [16] have used a conceptually different technique to suppress spectral contamination due to fragmentation effects.…”

“…In the past ten years, clusters containing an aromatic molecule and several rare gas atoms have been studied by a number of groups [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Two dominant motivations underly the great interest in these systems.…”

“…More recently, M. Schmidt, M. Mons, and J. LeCalv6 [ 10] have employed R2P2CI to record the spectra of Bz-Ar n (n = 1 -10), observing two classes of isomers. Bieske et al [15,16]. Since the early work of A. Amirav et al [13], An-Arn have also been studied by Ph.…”