Goncharov Alexander F, Crowhurst Jonathan C
Lawrence Livermore National Laboratory, University of California, 7000 East Avenue, Livermore, California 94551, USA.
Phys Rev Lett. 2006 Feb 10;96(5):055504. doi: 10.1103/PhysRevLett.96.055504. Epub 2006 Feb 7.
Raman measurements of molecular hydrogen ( and ) and nitrogen () have been made under simultaneous conditions of high temperature and high static pressure. Measurements have been made on H2 and D2 to 50 GPa and 1600 K, and on to 50 GPa and 2000 K. In all three materials the familiar molecular stretching mode (vibron) is accompanied in the high-temperature Raman spectra by one or more lower-frequency peaks due to transitions from excited vibrational states. We find that the frequency differences between these bands decreases with pressure, implying that the anharmonicity of the corresponding part of the intramolecular potential also decreases. This is accompanied by an increase in the measured linewidths of the bands that is consistent with a decrease of the depth of the potential and an approaching molecular dissociation.
在高温和高静水压的同时条件下，对分子氢（H₂和D₂）和氮气（N₂）进行了拉曼测量。已对H₂和D₂在高达50吉帕斯卡和1600开尔文的条件下进行了测量，对N₂在高达50吉帕斯卡和2000开尔文的条件下进行了测量。在所有这三种材料中，在高温拉曼光谱中，常见的分子拉伸模式（振子）伴随着由于从激发振动态跃迁而产生的一个或多个低频峰。我们发现这些谱带之间的频率差随压力减小，这意味着分子内势能相应部分的非谐性也减小。这伴随着所测谱带线宽的增加，这与势能深度的减小和分子解离的临近是一致的。
