Aging effects on translational lattice vibrations in ice I-h

Laser-Raman spectra of Vostok ice recovered from Antarctica have been measured in a frequency range of 10-400 cm(-1) in order to observe long-term aging effects on Raman spectra of ice Th We found that the intensity of the peak at 300 cm(-1) increased as the depth of the ice core increased from 500 to 2452 m. Since no change in the peak height was observed by pressurization, the increase of the peak intensity is attributed to the aging effect on a structural change of ice during a very long period from 28 000 to 209 000 yr. Since this peak is assigned to a translational lattice vibration traveling along the hydrogen bonds, we conclude that the proton arrangement in the Antarctic ice varies with a very long term aging.