论文标题
水从第一原理中的核旋转式旋转过渡
The nuclear-spin-forbidden rovibrational transitions of water from first principles
论文作者
论文摘要
水分子发生在两个核旋转异构体中，这些异构体因氢原子的总核自旋的值而异，即para-h $ _2 $ o $ _2 $ o和$ i = 1 $ i = 1 $ i = 0 $，ortho-h $ _2 $ o。由于仅观察到$ \ sim30 $ kHz的微小核旋转相互作用，矫正水和para水之间的光谱过渡极为弱。我们报告了H $ _2 $$^{16} $ O中的超细效应和正para转变的首次综合理论研究，这是由于核旋转和自旋旋转相互作用所致。我们还介绍了我们新开发的一般变异方法的细节，以模拟多原子分子中的超精细作用。我们对水的结果表明，最强的正para过渡，具有室温强度的订单为$ 10^{ - 31} $ cm/com/molecule的数量级比以前预测的值大，应在中央三级$ν_2$中可检测到$ 2 $和近2 $ $ n-frared $2ν_1+ν_2$和$ν_2$ n C+ν_2$ν_2+n名n C+ν_1+ν_1+n。光谱实验。
The water molecule occurs in two nuclear-spin isomers that differ by the value of the total nuclear spin of the hydrogen atoms, i.e., $I=0$ for para-H$_2$O and $I=1$ for ortho-H$_2$O. Spectroscopic transitions between rovibrational states of ortho and para water are extremely weak due to the tiny hyperfine nuclear-spin-rotation interaction of only $\sim30$ kHz and so far were not observed. We report the first comprehensive theoretical investigation of the hyperfine effects and ortho-para transitions in H$_2$$^{16}$O due to nuclear-spin-rotation and spin-spin interactions. We also present the details of our newly developed general variational approach to the simulation of hyperfine effects in polyatomic molecules. Our results for water suggest that the strongest ortho-para transitions with room-temperature intensities on the order of $10^{-31}$ cm/molecule are about an order of magnitude larger than previously predicted values and should be detectable in the mid-infrared $ν_2$ and near-infrared $2ν_1+ν_2$ and $ν_1+ν_2+ν_3$ bands by current spectroscopy experiments.
