Can ortho-para transitions for water be observed?
Can ortho-para transitions for water be observed?
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DOI：
10.1063/1.1633261
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发表时间：
2004-02-08
影响因子：
4.4
通讯作者：
Tennyson, J
中科院分区：
文献类型：
--
作者：
Miani, A;Tennyson, J
水的光谱可以被认为是两个分子的光谱的并列，具有不同的总核自旋：邻-H（2）O和对-H（2）O。在两种不同的核自旋同位素之间没有观察到跃迁。相互转换的时间是未知的，人们普遍认为，相互转换是禁止没有一些其他的干预。然而，弱的核自旋旋转相互作用发生，并可以驱动邻位到帕拉的转变。从头计算结果表明，超精细核自旋-转动耦合常数约为30 kHz。这些常数被用来探索整个振动-旋转光谱，特别强调附近能级之间的耦合。预测不同的光谱区域，最强的邻位和帕拉水平的水之间的过渡可以通过实验观察。(C)2004年，美国物理学会。
The spectrum of water can be considered as the juxtaposition of the spectra of two molecules, with different total nuclear spin: ortho-H(2)O, and para-H(2)O. No transitions have ever been observed between the two different nuclear-spin isotopomers. The interconversion time is unknown and it is widely assumed that interconversion is forbidden without some other intervention. However, weak nuclear spin-rotation interaction occurs and can drive ortho to para transitions. Ab initio calculations show that the hyperfine nuclear spin-rotational coupling constants are about 30 kHz. These constants are used to explore the whole vibration-rotation spectrum with special emphasis on the coupling between nearby levels. Predictions are made for different spectral regions where the strongest transitions between ortho and para levels of water could be experimentally observed. (C) 2004 American Institute of Physics.