FTIR signatures of type-II clathrates of carbon dioxide in natural quartz veins

Abstract

In situ FTIR spectroscopy is used to probe the clathrate formation in H 2 O-CO 2 inclusion in quartz veins by monitoring the spectral variations in 300-93 K. The characteristic spectral signatures of asymmetric stretching mode (V 3 ) of CO 2 clathrates in both structure-I and structure-II are doublets at 2336, 2348 cm -1 , and 2337, 2349 cm -1 respectively. Further, structure-II for CO 2 clathrate is metastable (it is stable in 93-215 K range), and it transforms into structure-I before melting.