Experimental and Theoretical Characterization of the 22A鈥测€?2A鈥?Transition of BeOH/D

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• 作者：Kyle J. Mascaritolo ; Jeremy M. Merritt ; Michael C. Heaven ; Per Jensen
• 刊名：Journal of Physical Chemistry A
• 出版年：2013
• 出版时间：December 19, 2013
• 年：2013
• 卷：117
• 期：50
• 页码：13654-13663
• 全文大小：351K
• 年卷期：v.117,no.50(December 19, 2013)
• ISSN：1520-5215

文摘

The hydroxides of Ca, Sr, and Ba are known to be linear molecules, while MgOH is quasilinear. High-level ab initio calculations for BeOH predict a bent equilibrium structure with a bond angle of 140.9掳, indicating a significant contribution of covalency to the bonding. However, experimental confirmation of the bent structure is lacking. In the present study, we have used laser excitation techniques to observe the 2²A鈥测€?²A鈥?transition of BeOH/D in the energy range of 30300鈥?2800 cm^鈥?. Rotationally resolved spectra were obtained, with sufficient resolution to reveal spin splittings for the electronically excited state. Two-color photoionization was used to determine an ionization energy of 66425(10) cm^鈥?. Ab initio calculations were used to guide the analysis of the spectroscopic data. Multireference configuration interaction calculations were used to construct potential energy surfaces for the 1²A鈥? 2²A鈥? and 1²A鈥?states. The rovibronic eigenstates supported by these surfaces were determined using the Morse oscillator rigid bender internal dynamics Hamiltonian. The theoretical results were in sufficiently good agreement with the experimental data to permit unambiguous assignment. It was confirmed that the equilibrium geometry of the ground state is bent and that the barrier to linearity lies below the zero-point energies for both BeOH and BeOD.