Calculation of infrared and Raman vibration modes of magnesite at high pressure by density-functional perturbation theory and comparison with experiments
Calculation of infrared and Raman vibration modes of magnesite at high pressure by density-functional perturbation theory and comparison with experiments
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DOI：
10.1007/s00269-010-0395-y
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发表时间：
2011-03-01
影响因子：
1.4
通讯作者：
Mainprice, David
中科院分区：
文献类型：
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作者：
Clark, Stewart J.;Jouanna, Paul;Mainprice, David
我们预测的IR-TO，IR-LO和拉曼模式（波数和强度）的菱镁矿（MgCO 3）高达50 GPa，在T = 0 K，使用密度泛函微扰理论的三阶微扰下，谐波假设。对10-30 GPa压力范围内的所有模式和50 GPa压力范围内的某些模式，将预测的IR-TO和拉曼模波数、模Gruneisen参数和Davydov分裂与实验数据进行了系统的比较。现有的实验允许将这种比较仅扩展到E-u（nu（3））非对称拉伸模式的IR-LO波数，从而证实了该模式在非常高的压力下的奇怪实验行为。预测的IRTO，IR-LO和拉曼强度高达50 GPa的只是列表，但数据丢失，他们与精确的实验比较。然而，一般良好的协议之间观察到的数值计算结果和实验数据，当它们的比较是可能的，表明第一原理方法是一个主要的帮助，以预测整个频谱非常高的压力。
We predict the IR-TO, IR-LO and Raman modes (wave numbers and intensities) of magnesite (MgCO3) up to 50 GPa, at T = 0 K, using the density-functional perturbation theory up to a third order perturbation, under the harmonic assumption. The predicted IR - TO and Raman mode wave numbers, the mode Gruneisen parameters and the Davydov splittings are systematically compared with experimental data for all modes up to the pressures of 10-30 GPa and for some modes up to 50 GPa. Existing experiments allow extending this comparison only to IR-LO wave numbers of the E-u (nu(3)) asymmetric - stretch mode, confirming the odd experimental behavior of this mode at very high pressures. Predicted IRTO, IR-LO and Raman intensities up to 50 GPa are just tabulated, but data are missing for their comparison with precise experiments. However, the generally good agreement observed between numerical results and experimental data, when their comparison is possible, suggests that first-principles methods are a major help to predict the entire spectrum up to very high pressures.