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Title: Silyl group internal rotation in [ital S][sub 1] phenylsilane and phenylsilane cation: Experiments and [ital ab] [ital initio] calculations

Abstract

Resonant two-photon ionization (R2PI) and pulsed field ionization (PFI) were used to measure [ital S][sub 1]--[ital S][sub 0] and cation--[ital S][sub 1] spectra of internally cold phenylsilane. We measure the adiabatic ionization potentials IP(phenylsilane)=73 680[plus minus]5 cm[sup [minus]1], IP(phenylsilane [center dot]Ar)=73 517[plus minus]5 cm[sup [minus]1] and IP(phenylsilane [center dot]Ar[sub 2])=73 359[plus minus]5 cm[sup [minus]1]. We assign many low lying torsion--vibration levels of the [ital S][sub 1] ([ital [tilde A]] [sup 1][ital A][sub 1]) state and of [ital [tilde X]] [sup 2][ital B][sub 1] of phenylsilane[sup +]. In both states, the pure torsional transitions are well fit by a simple sixfold hindered rotor Hamiltonian. The results for the rotor inertial constant [ital B] and internal rotation potential barrier [ital V][sub 6] are, in [ital S][sub 1], [ital B]=2.7[plus minus]0.2 cm[sup [minus]1] and [ital V][sub 6]=[minus]44[plus minus]4 cm[sup [minus]1]; in the cation, [ital B]=2.7[plus minus]0.2 cm[sup [minus]1] and [ital V][sub 6]=+19[plus minus]3 cm[sup [minus]1]. The sign of [ital V][sub 6] and the conformation of minimum energy are inferred from spectral intensities of bands terminating on the 3[ital a][sup [double prime]][sub 1] and 3[ital a][sup [double prime]][sub 2] torsional levels. In [ital S][sub 1] the staggered conformation is most stable, while in themore » cation ground state the eclipsed conformation is most stable. For all sixfold potentials whose absolute phase is known experimentally, the most stable conformer is staggered in the neutral states ([ital S][sub 0] and [ital S][sub 1] [ital p]-fluorotoluene, [ital S][sub 1] toluene, [ital S][sub 1] [ital p]-fluorotoluene) and eclipsed in the cationic states (ground state toluene[sup +] and phenylsilane[sup +]).« less

Authors:
;  [1]
  1. Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
Publication Date:
OSTI Identifier:
6024094
DOE Contract Number:  
FG02-92ER14306
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics; (United States)
Additional Journal Information:
Journal Volume: 99:6; Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ARGON COMPLEXES; IONIZATION POTENTIAL; SILANES; ADIABATIC PROCESSES; ATOMS; CATIONS; ENERGY SPECTRA; HAMILTONIANS; MOLECULES; MULTI-PHOTON PROCESSES; PHOTOIONIZATION; PULSES; RESONANCE ABSORPTION; ABSORPTION; CHARGED PARTICLES; COMPLEXES; HYDRIDES; HYDROGEN COMPOUNDS; IONIZATION; IONS; MATHEMATICAL OPERATORS; ORGANIC COMPOUNDS; ORGANIC SILICON COMPOUNDS; QUANTUM OPERATORS; SILICON COMPOUNDS; SORPTION; SPECTRA; 664200* - Spectra of Atoms & Molecules & their Interactions with Photons- (1992-); 664400 - Experimentally Derived Information on Atomic & Molecular Properties- (1992-)

Citation Formats

Lu, K, and Weisshaar, J C. Silyl group internal rotation in [ital S][sub 1] phenylsilane and phenylsilane cation: Experiments and [ital ab] [ital initio] calculations. United States: N. p., 1993. Web. doi:10.1063/1.466079.
Lu, K, & Weisshaar, J C. Silyl group internal rotation in [ital S][sub 1] phenylsilane and phenylsilane cation: Experiments and [ital ab] [ital initio] calculations. United States. https://doi.org/10.1063/1.466079
Lu, K, and Weisshaar, J C. 1993. "Silyl group internal rotation in [ital S][sub 1] phenylsilane and phenylsilane cation: Experiments and [ital ab] [ital initio] calculations". United States. https://doi.org/10.1063/1.466079.
@article{osti_6024094,
title = {Silyl group internal rotation in [ital S][sub 1] phenylsilane and phenylsilane cation: Experiments and [ital ab] [ital initio] calculations},
author = {Lu, K and Weisshaar, J C},
abstractNote = {Resonant two-photon ionization (R2PI) and pulsed field ionization (PFI) were used to measure [ital S][sub 1]--[ital S][sub 0] and cation--[ital S][sub 1] spectra of internally cold phenylsilane. We measure the adiabatic ionization potentials IP(phenylsilane)=73 680[plus minus]5 cm[sup [minus]1], IP(phenylsilane [center dot]Ar)=73 517[plus minus]5 cm[sup [minus]1] and IP(phenylsilane [center dot]Ar[sub 2])=73 359[plus minus]5 cm[sup [minus]1]. We assign many low lying torsion--vibration levels of the [ital S][sub 1] ([ital [tilde A]] [sup 1][ital A][sub 1]) state and of [ital [tilde X]] [sup 2][ital B][sub 1] of phenylsilane[sup +]. In both states, the pure torsional transitions are well fit by a simple sixfold hindered rotor Hamiltonian. The results for the rotor inertial constant [ital B] and internal rotation potential barrier [ital V][sub 6] are, in [ital S][sub 1], [ital B]=2.7[plus minus]0.2 cm[sup [minus]1] and [ital V][sub 6]=[minus]44[plus minus]4 cm[sup [minus]1]; in the cation, [ital B]=2.7[plus minus]0.2 cm[sup [minus]1] and [ital V][sub 6]=+19[plus minus]3 cm[sup [minus]1]. The sign of [ital V][sub 6] and the conformation of minimum energy are inferred from spectral intensities of bands terminating on the 3[ital a][sup [double prime]][sub 1] and 3[ital a][sup [double prime]][sub 2] torsional levels. In [ital S][sub 1] the staggered conformation is most stable, while in the cation ground state the eclipsed conformation is most stable. For all sixfold potentials whose absolute phase is known experimentally, the most stable conformer is staggered in the neutral states ([ital S][sub 0] and [ital S][sub 1] [ital p]-fluorotoluene, [ital S][sub 1] toluene, [ital S][sub 1] [ital p]-fluorotoluene) and eclipsed in the cationic states (ground state toluene[sup +] and phenylsilane[sup +]).},
doi = {10.1063/1.466079},
url = {https://www.osti.gov/biblio/6024094}, journal = {Journal of Chemical Physics; (United States)},
issn = {0021-9606},
number = ,
volume = 99:6,
place = {United States},
year = {1993},
month = {9}
}