[In-situ Raman spectroscopic study of serpentine using diamond anvil cell]

Within the diamond anvil cell, the Raman spectroscopic study of serpentine was operated at room temperature and under pressures from 1 atm to 5 140 MPa. This study analyzed the pressure dependence of the low-frequency Raman vibrational modes of serpentine at 388, 471, 692 and 705 cm(-1) respectively. The vibrational modes of inner OH groups at 3 664 cm(-1) and inter-layer OH groups at 3 696 cm(-1) shifted linearly with the increasing pressures. The pressure-related slope of 3 664 cm(-1) was 3.3 cm(-1) x GPa(-1). The vibrational mode at 3 696 cm(-1) of the inter-layer hydroxyl shifted upwards with the pressure-related slope 8. 3 cm(-1) x GPa(-1) up to 2.0 GPa, and then with 1.1 cm(-1) GPa(-1) from 2.0 GPa to ca. 5.0 GPa. It could be interpreted that the hydrogen bond of the inter-layer hydroxyl made dominant contribution to such experimental phenomena. In addition, the dehydration of serpentine did not occur under such conditions.