@article { ISI:000342209400034, title = {Collision dynamics of polyatomic molecules containing carbon rings at low temperatures}, journal = {JOURNAL OF CHEMICAL PHYSICS}, volume = {141}, number = {10}, year = {2014}, month = {SEP 14}, pages = {104317}, publisher = {AMER INST PHYSICS}, address = {CIRCULATION \& FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA}, abstract = {We explore the collision dynamics of complex hydrocarbon molecules (benzene, coronene, adamantane, and anthracene) containing carbon rings in a cold buffer gas of He-3. For benzene, we present a comparative analysis of the fully classical and fully quantum calculations of elastic and inelastic scattering cross sections at collision energies between 1 and 10 cm(-1). The quantum calculations are performed using the time-independent coupled channel approach and the coupled-states approximation. We show that the coupled-states approximation is accurate at collision energies between 1 and 20 cm(-1). For the classical dynamics calculations, we develop an approach exploiting the rigidity of the carbon rings and including low-energy vibrational modes without holonomic constraints. Our results illustrate the effect of the molecular shape and the vibrational degrees of freedom on the formation of long-lived resonance states that lead to low-temperature clustering. (c) 2014 AIP Publishing LLC.}, issn = {0021-9606}, doi = {10.1063/1.4894793}, author = {Li, Zhiying and Krems, Roman V. and Heller, Eric J.} }