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Title: Vibrational predissociation of benzene dimers and trimer by the crossed laser-molecular beam technique

Abstract

A molecular beam composed predominantly of benzene monomer, dimer, and trimer is excited with tunable, pulsed, infrared radiation in the C-H stretch frequency range (3000 to 3100 cm/sup -1/). Two types of experiments are performed for the observation of the vibrational predissociation of the excited cluster, measuring directly the wavelength dependence of the predissociation yield and the translational energy distribution of the predissociation products. The wavelength dependence of the vibrational predissociation is found to be similar to the infrared spectra of room-temperature liquid benzene. The translational energy distributions of the predissociation products are used to deduce dynamical properties for the following predissociation mechanism: (C/sub 6/H/sub 6/)/sub n/ + hv ..-->.. (C/sub 6/H/sub 6/)/sub n-1/ + C/sub 6/H/sub 6/** (tau), where ** indicates vibrational excitation. The lifetime, tau, of the vibrationally excited clusters is determined to be in the range of 10/sup -12/ < tau < 10/sup -6/ s. The most probable predissociation is characterized by all of the excess energy appearing in the rotational and vibrational motions of the products. The two product molecules do not seem to share this excess energy equally, the monomer product retaining in excess of 2/3 of the available energy. These observations are qualitatively consistentmore » with current theories of vibrational predissociation of weekly bound molecular clusters.« less

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Lawrence Berkeley Lab., CA
OSTI Identifier:
6071361
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Journal Article
Journal Name:
J. Phys. Chem.; (United States)
Additional Journal Information:
Journal Volume: 85:22
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BENZENE; PHOTOLYSIS; DIMERS; INFRARED RADIATION; LASERS; MOLECULAR BEAMS; MONOMERS; PRESSURE DEPENDENCE; PULSED IRRADIATION; AROMATICS; BEAMS; CHEMICAL REACTIONS; DECOMPOSITION; ELECTROMAGNETIC RADIATION; HYDROCARBONS; IRRADIATION; ORGANIC COMPOUNDS; PHOTOCHEMICAL REACTIONS; RADIATIONS; 400500* - Photochemistry

Citation Formats

Vernon, M F, Lisy, J M, Kwok, H S, Krajnovich, D J, Tramer, A, Shen, Y R, and Lee, Y T. Vibrational predissociation of benzene dimers and trimer by the crossed laser-molecular beam technique. United States: N. p., 1981. Web. doi:10.1021/j150622a024.
Vernon, M F, Lisy, J M, Kwok, H S, Krajnovich, D J, Tramer, A, Shen, Y R, & Lee, Y T. Vibrational predissociation of benzene dimers and trimer by the crossed laser-molecular beam technique. United States. doi:10.1021/j150622a024.
Vernon, M F, Lisy, J M, Kwok, H S, Krajnovich, D J, Tramer, A, Shen, Y R, and Lee, Y T. Thu . "Vibrational predissociation of benzene dimers and trimer by the crossed laser-molecular beam technique". United States. doi:10.1021/j150622a024.
@article{osti_6071361,
title = {Vibrational predissociation of benzene dimers and trimer by the crossed laser-molecular beam technique},
author = {Vernon, M F and Lisy, J M and Kwok, H S and Krajnovich, D J and Tramer, A and Shen, Y R and Lee, Y T},
abstractNote = {A molecular beam composed predominantly of benzene monomer, dimer, and trimer is excited with tunable, pulsed, infrared radiation in the C-H stretch frequency range (3000 to 3100 cm/sup -1/). Two types of experiments are performed for the observation of the vibrational predissociation of the excited cluster, measuring directly the wavelength dependence of the predissociation yield and the translational energy distribution of the predissociation products. The wavelength dependence of the vibrational predissociation is found to be similar to the infrared spectra of room-temperature liquid benzene. The translational energy distributions of the predissociation products are used to deduce dynamical properties for the following predissociation mechanism: (C/sub 6/H/sub 6/)/sub n/ + hv ..-->.. (C/sub 6/H/sub 6/)/sub n-1/ + C/sub 6/H/sub 6/** (tau), where ** indicates vibrational excitation. The lifetime, tau, of the vibrationally excited clusters is determined to be in the range of 10/sup -12/ < tau < 10/sup -6/ s. The most probable predissociation is characterized by all of the excess energy appearing in the rotational and vibrational motions of the products. The two product molecules do not seem to share this excess energy equally, the monomer product retaining in excess of 2/3 of the available energy. These observations are qualitatively consistent with current theories of vibrational predissociation of weekly bound molecular clusters.},
doi = {10.1021/j150622a024},
journal = {J. Phys. Chem.; (United States)},
number = ,
volume = 85:22,
place = {United States},
year = {1981},
month = {10}
}