Deleuze M S, Knippenberg S
Theoretical Physical Chemistry, Department SBG, Hasselt University, Agoralaan, Gebouw D, B-3590 Diepenbeek, Belgium.
J Chem Phys. 2006 Sep 14;125(10):104309. doi: 10.1063/1.2209690.
The scope of the present work is to reconcile electron momentum spectroscopy with elementary thermodynamics, and refute conclusions drawn by Saha et al. in J. Chem. Phys. 123, 124315 (2005) regarding fingerprints of the gauche conformational isomer of 1,3-butadiene in electron momentum distributions that were experimentally inferred from gas phase (e,2e) measurements on this compound [M. J. Brunger et al., J. Chem. Phys. 108, 1859 (1998)]. Our analysis is based on thorough calculations of one-electron and shake-up ionization spectra employing one-particle Green's function theory along with the benchmark third-order algebraic diagrammatic construction [ADC(3)] scheme. Accurate spherically averaged electron momentum distributions are correspondingly computed from the related Dyson orbitals. The ionization spectra and Dyson orbital momentum distributions that were computed for the trans-conformer of 1,3-butadiene alone are amply sufficient to quantitatively unravel the shape of all available experimental (e,2e) electron momentum distributions. A comparison of theoretical ADC(3) spectra for the s-trans and gauche energy minima with inner- and outer-valence high-resolution photoelectron measurements employing a synchrotron radiation beam [D. M. P. Holland et al., J. Phys. B 29, 3091 (1996)] demonstrates that the gauche structure is incompatible with ionization experiments in high-vacuum conditions and at standard temperatures. On the other hand, outer-valence Green's function calculations on the s-trans energy minimum form and approaching basis set completeness provide highly quantitative insights, within approximately 0.2 eV accuracy, into the available experimental one-electron ionization energies. At last, analysis of the angular dependence of relative (e,2e) ionization intensities nicely confirms the presence of one rather intense pi(-2) pi(*+1) satellite at approximately 13.1 eV in the ionization spectrum of the s-trans conformer.
本工作的范围是使电子动量谱与基础热力学相协调，并反驳萨哈等人在《化学物理杂志》123, 124315 (2005) 中得出的关于1,3 - 丁二烯gauche构象异构体在电子动量分布中的指纹特征的结论，这些指纹特征是从对该化合物的气相 (e,2e) 测量中实验推断出来的 [M. J. 布伦格等人，《化学物理杂志》108, 1859 (1998)]。我们的分析基于采用单粒子格林函数理论以及基准三阶代数图示构建 [ADC(3)] 方案对单电子和振激电离光谱进行的全面计算。相应地，从相关的戴森轨道计算出精确的球对称平均电子动量分布。仅针对1,3 - 丁二烯反式构象异构体计算出的电离光谱和戴森轨道动量分布足以定量解析所有现有的实验 (e,2e) 电子动量分布的形状。将s - 反式和gauche能量极小值的理论ADC(3) 光谱与采用同步辐射束的内价和外价高分辨率光电子测量结果 [D. M. P. 霍兰德等人，《物理杂志B》29, 3091 (1996)] 进行比较表明，gauche结构与高真空条件和标准温度下的电离实验不相符。另一方面，对s - 反式能量极小值形式并接近基组完备性的外价格林函数计算，能在约0.2 eV的精度内对现有的实验单电子电离能提供高度定量的见解。最后，对相对 (e,2e) 电离强度的角度依赖性分析很好地证实了在s - 反式构象异构体的电离光谱中，在约13.1 eV处存在一个相当强的π(-2)π(* + 1) 卫星峰。
