Johnston M David, Gentry Matthew R, Metz Ricardo B
Department of Chemistry , University of Massachusetts Amherst , Amherst , Massachusetts 01003 , United States.
J Phys Chem A. 2018 Oct 11;122(40):8047-8053. doi: 10.1021/acs.jpca.8b07849. Epub 2018 Oct 2.
Density functional and ab initio calculations, along with photodissociation spectroscopy and ion imaging of MnO from 21,300 to 33,900 cm, are used to probe the photodissociation dynamics and bond strength of the manganese oxide cation (MnO). These studies confirm the theoretical ground state (Π) and determine the spin-orbit constant ( A' = 14 cm) of the dominant optically accessible excited state (Π) in the region. Photodissociation via this excited Π state results in ground state Mn (S) + O (P) products. At energies above 30,000 cm, the Mn (S) + O (P) channel is energetically accessible and becomes the preferred dissociation pathway. The bond dissociation energy ( D = 242 ± 5 kJ/mol) of MnO is measured from several images of each photofragmentation channel and compared to theory, resolving a disagreement in previous measurements. MRCI+Q calculations are much more successful in predicting the observed spectrum than TD-DFT or EOM-CCSD calculations.
密度泛函和从头算计算，以及对21300至33900厘米范围内的MnO进行光解离光谱和离子成像，用于探究氧化锰阳离子（MnO）的光解离动力学和键强度。这些研究证实了理论基态（Π），并确定了该区域内主要光学可及激发态（Π）的自旋轨道常数（A' = 14厘米）。通过这种激发的Π态进行光解离会产生基态Mn（S）+ O（P）产物。在能量高于30000厘米时，Mn（S）+ O（P）通道在能量上是可及的，并成为首选的解离途径。通过每个光解离通道的多个图像测量了MnO的键解离能（D = 242±5 kJ/mol），并与理论进行了比较，解决了先前测量中的分歧。与TD-DFT或EOM-CCSD计算相比，MRCI+Q计算在预测观测光谱方面要成功得多。
