Dynamics and free energies of CH4 and CO2 in the molecular solid of the p-tert-butylcalix[4]arene

The dynamics of the guest molecules CO2 and CH4 in p-tert-butylcalix[4]arene (TBC4) motion were studied from 100 K to 400 K using molecular simulation techniques. The rattling motion of the guest molecules was characterized by velocity autocorrelation functions, with CO2 and CH4 showing very different temperature dependence.