Alijah Alexander, Hinze Juergen
Departamento de Química, Universidade de Coimbra, 3004-535 Coimbra, Portugal.
Philos Trans A Math Phys Eng Sci. 2006 Nov 15;364(1848):2877-88. doi: 10.1098/rsta.2006.1860.
We discuss recent progress in the calculation and identification of rotation-vibrational states of H3+ at intermediate energies up to 13,000 cm(-1). Our calculations are based on the potential energy surface of Cencek et al. which is of sub-microhartree accuracy. As this surface includes diagonal adiabatic and relativistic corrections to the fixed nuclei electronic energies, the remaining discrepancies between our calculated and experimental data should be due to the neglect of non-adiabatic coupling to excited electronic states in the calculations. To account for this, our calculated energy values were adjusted empirically by a simple correction formula. Based on our understanding of the adiabatic approximation, we suggest two new approaches to account for the off-diagonal adiabatic correction, which should work; however, they have not been tested yet for H3+. Theoretical predictions made for the above-barrier energy region of recent experimental interest are accurate to 0.35 cm(-1) or better.
我们讨论了在高达13000厘米⁻¹的中等能量下，H₃⁺转动 - 振动状态的计算和识别方面的最新进展。我们的计算基于Cencek等人的势能面，其精度达到亚微哈特里。由于该势能面包含对固定核电子能量的对角绝热和相对论修正，我们计算数据与实验数据之间的剩余差异应该是由于计算中忽略了与激发电子态的非绝热耦合。为了解决这个问题，我们通过一个简单的校正公式对计算出的能量值进行了经验性调整。基于我们对绝热近似的理解，我们提出了两种新的方法来考虑非对角绝热修正，这两种方法应该可行；然而，它们尚未针对H₃⁺进行测试。对于近期实验感兴趣的高于势垒能量区域所做的理论预测，其精度达到0.35厘米⁻¹或更高。
