Dynamic properties of methane, water and methane hydrates using computational simulations

Abstract

In this study, the vibrational spectrum of methane hydrates is calculated through dynamic molecular simulations based on two different methods. The spectra obtained using the proposed procedure allow the differentiation of the contributions of different inter- and intramolecular motion types in the spectrum, which cannot be produced with the traditional method based on atomic velocities. Simulations were carried out at different composition, pressure and temperature conditions to observe the effect of these variables on the vibrational spectrum. The proposed method allowed the observation of a difference in the frequencies for the C–H stretching vibrations between small and large cavities, which agrees with reported experimental values.

Keywords:

• methane hydrate
• molecular dynamics
• vibrational spectrum
• autocorrelation functions