title: Mechanisms for the far-infrared absorption in liquid methane.
abstract: The time correlation function for the induced dipole moment in liquid methane was computed from molecular dynamics computer simulations for a thermodynamic state at a temperature of 122.2 K and density of 25.34 mol/l. We included first-order induction mechanisms from the electric fields emanated by octupole and hexadecapole moments, their field gradients, as well as electronic superposition. The octupole-induced dipole represents the most important contribution to the far-infrared absorption spectrum. However, additional mechanisms are important for absorption in liquid methane. By comparing the computed absorption line shape with the experimental spectrum, we found a very satisfactory agreement between the two if we account for detailed balancing.
authors.affiliation: Grupo de Química Teórica, Instituto de Química, UFRGS, Porto Alegre, RS-91540-000, Brazil.
authors.forename: N B Huamán
authors.initials: NB
authors.lastname: Lozano
authors.forename: H
authors.initials: H
authors.lastname: Stassen