Rotational distributions following van der Waals molecule dissociation: comparison between experiment and theory for benzene-Ar.

Content Provider	Semantic Scholar
Author	Sampson, Rebecca K. Bellm, Susan M. McCaffery, Anthony J. Lawrance, Warren D.
Copyright Year	2005
Abstract	The translational energy release distribution for dissociation of benzene-Ar has been measured and, in combination with the 6(1)(0) rotational contour of the benzene product observed in emission, used to determine the rotational J,K distribution of 0(0) benzene products formed during dissociation from 6(1). Significant angular momentum is transferred to benzene on dissociation. The 0(0) rotational distribution peaks at J=31 and is skewed to low K:Javerage=27, (K)average=10.3. The average angle between the total angular momentum vector and the unique rotational axis is determined to be 68 degrees. This indicates that benzene is formed tumbling about in-plane axes rather than in a frisbeelike motion, consistent with Ar "pushing off" benzene from an off-center position above or below the plane. The J distribution is very well reproduced by angular momentum model calculations based on an equivalent rotor approach [A. J. McCaffery, M. A. Osborne, R. J. Marsh, W. D. Lawrance, and E. R. Waclawik, J. Chem. Phys. 121, 1694 (2004)], indicating that angular momentum constraints control the partitioning of energy between translation and rotation. Calculations for p-difluorobenzene-Ar suggest that the equivalent rotor model can provide a reasonable prediction of both J and K distributions in prolate (or near prolate) tops when dissociation leads to excitation about the unique, in-plane axis. Calculations for s-tetrazine-Ar require a small maximum impact parameter to reproduce the comparatively low J values seen for the s-tetrazine product. The three sets of calculations show that the maximum impact parameter is not necessarily equal to the bond length of the equivalent rotor and must be treated as a variable parameter. The success of the equivalent rotor calculations argues that angular momentum constraints control the partitioning between rotation and translation of the products.
Starting Page	074311
Ending Page	074311
Page Count	1
File Format	PDF HTM / HTML
DOI	10.1063/1.1847512
PubMed reference number	15743236
Journal	Medline
Volume Number	122
Issue Number	7
Alternate Webpage(s)	https://dspace.flinders.edu.au/xmlui/bitstream/handle/2328/8815/2005101549.pdf?isAllowed=y&sequence=1
Alternate Webpage(s)	https://doi.org/10.1063/1.1847512
Journal	The Journal of chemical physics
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article