title: Alkylation effects on the energy transfer of highly vibrationally excited naphthalene.
abstract: The energy transfer of highly vibrationally excited isomers of dimethylnaphthalene and 2-ethylnaphthalene in collisions with krypton were investigated using crossed molecular beam/time-of-flight mass spectrometer/time-sliced velocity map ion imaging techniques at a collision energy of approximately 300 cm(-1). Angular-resolved energy-transfer distribution functions were obtained directly from the images of inelastic scattering. The results show that alkyl-substituted naphthalenes transfer more vibrational energy to translational energy than unsubstituted naphthalene. Alkylation enhances the V→T energy transfer in the range -ΔE(d)=-100~-1500 cm(-1) by approximately a factor of 2. However, the maximum values of V→T energy transfer for alkyl-substituted naphthalenes are about 1500~2000 cm(-1), which is similar to that of naphthalene. The lack of rotation-like wide-angle motion of the aromatic ring and no enhancement in very large V→T energy transfer, like supercollisions, indicates that very large V→T energy transfer requires special vibrational motions. This transfer cannot be achieved by the low-frequency vibrational motions of alkyl groups.
authors.affiliation: Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan.
authors.forename: Hsu Chen
authors.initials: HC
authors.lastname: Hsu
authors.forename: Ming-Tsang
authors.initials: MT
authors.lastname: Tsai
authors.forename: Yuri A
authors.initials: YA
authors.lastname: Dyakov
authors.forename: Chi-Kung
authors.initials: CK
authors.lastname: Ni