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

摘要

In situ FTIR spectroscopy is used to probe the clathrate formation in H2O–CO2 inclusion in quartz veins by monitoring the spectral variations in 300–93 K. The characteristic spectral signatures of asymmetric stretching mode (v_3) of CO2 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.