Vibrational Analysis of an Ice Ih Model from 0 to 4000 cm鈥? Using the Ab Initio WHBB Potential Energy Surface

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• 作者：Hanchao Liu ; Yimin Wang ; Joel M. Bowman
• 刊名：Journal of Physical Chemistry B
• 出版年：2013
• 出版时间：August 29, 2013
• 年：2013
• 卷：117
• 期：34
• 页码：10046-10052
• 全文大小：346K
• 年卷期：v.117,no.34(August 29, 2013)
• ISSN：1520-5207

文摘

We present an analysis of the vibrational modes of a model of hexagonal ice, ice Ih, comprised of 192 monomers with a core region of 105 monomers, using the ab initio WHBB potential energy surface [Wang, Y.; Shepler, B.; Braams, B.; Bowman, J. M. J. Chem. Phys. 2011, 134, 094509]. A standard normal-mode analysis and a local-monomer normal-mode analysis of 105 core monomers are performed to obtain harmonic frequencies and state densities of the 鈥減seudo-translation鈥?(0鈥?00 cm^鈥?), 鈥渓ibration鈥?(500鈥?100 cm^鈥?), monomer bend fundamental (1600 cm), and O鈥揌 stretch (3000鈥?700 cm^鈥?) bands. In addition, the coupled local-monomer model is used to obtain the vibrational density of states in the bend fundamental and O鈥揌 stretch regions. The harmonic and local-monomer vibrational density of states obtained from core monomers are in good agreement with those of inelastic neutron scattering spectra, especially the latter, which accounts for anharmonic coupling of monomer modes. Full deuteration is also considered, and the vibrational density of states is again compared to experiment, where good agreement is found.