Piszczatowski Konrad, Łach Grzegorz, Przybytek Michal, Komasa Jacek, Pachucki Krzysztof, Jeziorski Bogumil
Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093, Warsaw, Poland, Center for Theoretical and Computational Chemistry, University of Oslo, P.O. Box 1033 Blindern, N-0315 Oslo, Norway, Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznań, Poland, and Institute of Theoretical Physics, University of Warsaw, Hoża 69, 00-681 Warsaw, Poland.
J Chem Theory Comput. 2009 Nov 10;5(11):3039-48. doi: 10.1021/ct900391p. Epub 2009 Sep 30.
The dissociation energy of molecular hydrogen is determined theoretically with a careful estimation of error bars by including nonadiabatic, relativistic, and quantum electrodynamics (QED) corrections. The relativistic and QED corrections were obtained at the adiabatic level of theory by including all contributions of the order α(2) and α(3) as well as the major (one-loop) α(4) term, where α is the fine-structure constant. The computed α(0), α(2), α(3), and α(4) components of the dissociation energy of the H2 isotopomer are 36 118.7978(2), -0.5319(3), -0.1948(2), and -0.0016(8) cm(-1), respectively, while their sum amounts to 36 118.0695(10) cm(-1), where the total uncertainty includes the estimated size (±0.0004 cm(-1)) of the neglected relativistic nonadiabatic/recoil corrections. The obtained theoretical value of the dissociation energy is in excellent agreement with the most recent experimental determination 36 118.0696(4) cm(-1) [J. Liu et al. J. Chem. Phys. 2009, 130, 174 306]. This agreement would have been impossible without inclusion of several subtle QED contributions which have not been considered, thus far, for molecules. A similarly good agreement is observed for the leading vibrational and rotational energy differences. For the D2 molecule we observe, however, a small disagreement between our value 36 748.3633(9) cm(-1) and the experimental result 36 748.343(10) cm(-1) obtained in a somewhat older and less precise experiment [Y. P. Zhang et al. Phys. Rev. Lett. 2004, 92, 203003]. The reason of this discrepancy is not known.
通过纳入非绝热、相对论和量子电动力学（QED）修正，在仔细估计误差范围的情况下从理论上确定了分子氢的离解能。相对论和QED修正是在绝热理论水平上获得的，包括α(2)和α(3)阶的所有贡献以及主要的（单圈）α(4)项，其中α是精细结构常数。H2同位素异构体离解能的计算得到的α(0)、α(2)、α(3)和α(4)分量分别为36 118.7978(2)、-0.5319(3)、-0.1948(2)和-0.0016(8) cm(-1)，而它们的总和为36 118.0695(10) cm(-1)，其中总不确定度包括被忽略的相对论非绝热/反冲修正的估计大小（±0.0004 cm(-1)）。获得的离解能理论值与最新的实验测定值36 118.0696(4) cm(-1) [J. Liu等人，《化学物理杂志》2009年，130卷，174 306页] 非常吻合。如果不纳入迄今为止尚未考虑的几个微妙的QED贡献，这种吻合是不可能的。对于主要的振动和转动能量差也观察到了类似的良好吻合。然而，对于D2分子，我们观察到我们的值36 748.3633(9) cm(-1)与在一个稍早且不太精确的实验 [Y. P. Zhang等人，《物理评论快报》2004年，92卷，203003页] 中获得的实验结果36 748.343(10) cm(-1)之间存在小的差异。这种差异的原因尚不清楚。
