Description:
<jats:p>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 ∼520cm−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 σ(naphthalene): σ(methylnaphthalene)=1.08±0.05:1. The energy transfer probability density function shows that naphthalene has a little larger probability at small T→V∕R energy transfer, ΔEu&lt;300cm−1, and 2-methylnaphthalene has a little larger probability at large V→T energy transfer, −800cm−1&lt;ΔEd&lt;−100cm−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 ΔEd&lt;−1500cm−1, was observed. The possible methylation effects due to the subsequent successive collisions were discussed.</jats:p>