title: Energy transfer of highly vibrationally excited 2-methylnaphthalene: Methylation effects.
abstract: The methylation effects in the energy transfer between Kr atoms and highly vibrationally excited 2-methylnaphthalene in the triplet state were investigated using crossed-beam/time-sliced velocity-map ion imaging at a translational collision energy of approximately 520 cm(-1). Comparison of the energy transfer between naphthalene and 2-methylnaphthalene shows that the difference in total collisional cross section and the difference in energy transfer probability density functions are small. The ratio of the total cross sections is sigma(naphthalene): sigma(methylnaphthalene)=1.08+/-0.05:1. The energy transfer probability density function shows that naphthalene has a little larger probability at small T-->VR energy transfer, DeltaE(u)<300 cm(-1), and 2-methylnaphthalene has a little larger probability at large V-->T energy transfer, -800 cm(-1)<DeltaE(d)<-100 cm(-1). However, these differences are close to our experimental uncertainty. No significant difference in the probability of very large energy transfer, such as supercollisions defined arbitrarily as DeltaE(d)<-1500 cm(-1), was observed. The possible methylation effects due to the subsequent successive collisions were discussed.
authors.affiliation: Institute of Atomic and Molecular Sciences, Academia Sinica, P.O. Box 23-166, Taipei 10617, Taiwan.
authors.forename: Hsu Chen
authors.initials: HC
authors.lastname: Hsu
authors.forename: Chen-Lin
authors.initials: CL
authors.lastname: Liu
authors.forename: Yuan Chin
authors.initials: YC
authors.lastname: Hsu
authors.forename: Chi-Kung
authors.initials: CK
authors.lastname: Ni