Stimson S, Evans M, Hsu C-W, Ng C Y
Ames Laboratory, U.S. DOE, and Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
J Chem Phys. 2007 Apr 28;126(16):164303. doi: 10.1063/1.2720843.
The authors have obtained rotationally resolved vacuum ultraviolet pulsed field ionization-photoelectron (vuv-PFI-PE) spectrum of HD in the photon energy range of 15.29-18.11 eV, covering the ionization transitions HD+(X 2Sigmag+,v+=0-21,N+)<--HD(X 1Sigmag+,v"=0,J"). The assignment of rotational transitions resolved in the vuv-PFI-PE vibrational bands for HD+(X 2Sigmag+,v+=0-20) and their simulation using the Buckingham-Orr-Sichel (BOS) model are presented. Rotational branches corresponding to the DeltaN=N+-J"=0, +/-1, +/-2, +/-3, and +/-4 transitions are observed in the vuv-PFI-PE spectrum of HD. The BOS simulation shows that the perturbation of vuv-PFI-PE rotational line intensities due to near resonance autoionization is very minor at v+>or=5 and decreases as v+ is increased. Thus, the rotationally resolved PFI-PE bands for HD+(v+>or=5) presented here provide reliable estimates of state-to-state cross sections for direct photoionization of HD, while the rotationally resolved PFI-PE bands for HD+(v+<5) are useful data for fundamental understanding of the near resonance autoionizing mechanism. On the basis of the rovibrational assignment of the vuv-PFI-PE bands, the ionization energies for the formation of HD+(X 2Sigmag+,v+=0-20,N+) from HD(X 1Sigmag+,v"=0,J") and the vibrational constants (omegae, omegaechie, omegaeye, and omegaeze), the rotational constants (Be and alphae), the vibrational energy spacings, and the dissociation energy for HD+(X 2Sigmag+) are determined. As expected, these values are found to be in excellent agreement with high level theoretical predictions.
作者获得了HD在15.29 - 18.11 eV光子能量范围内的转动分辨真空紫外脉冲场电离光电子（vuv - PFI - PE）光谱，涵盖了电离跃迁HD+(X 2Σg +,v +=0 - 21,N +)←--HD(X 1Σg +,v" = 0,J")。本文给出了HD+(X 2Σg +,v +=0 - 20)在vuv - PFI - PE振动带中分辨出的转动跃迁归属及其使用Buckingham - Orr - Sichel（BOS）模型的模拟结果。在HD的vuv - PFI - PE光谱中观察到了对应于ΔN = N + - J" = 0,±1,±2,±3和±4跃迁的转动支。BOS模拟表明，在v +≥5时，近共振自电离对vuv - PFI - PE转动线强度的扰动非常小，并且随着v +的增加而减小。因此，这里给出的HD+(v +≥5)的转动分辨PFI - PE带为HD直接光电离的态 - 态截面提供了可靠的估计，而HD+(v +<5)的转动分辨PFI - PE带是用于深入理解近共振自电离机制的有用数据。基于vuv - PFI - PE带的振转归属，确定了由HD(X 1Σg +,v" = 0,J")形成HD+(X 2Σg +,v +=0 - 20,N +)的电离能以及振动常数（ωe、ωechi、ωeye和ωeze）、转动常数（Be和αe）、振动能量间距和HD+(X 2Σg +)的离解能。正如预期那样，发现这些值与高水平理论预测非常吻合。
