Multireference X-Ray Emission and Absorption Spectroscopy calculations from Monte Carlo Configuration Interaction

Abstract

We adapt the method of Monte Carlo configuration interaction to calculate core-hole states and use this for the computation of X-ray emission and absorption values. We consider CO, CH${}_4$, NH${}_3$, H${}_2$O, HF, HCN, CH${}_3$OH, CH${}_3$F, HCl and NO using a 6-311G** basis. We also look at carbon monoxide with a stretched geometry and discuss the dependence of its results on the cutoff used. The Monte Carlo configuration interaction results are compared with EOM-CCSD values for X-ray emission and with experiment for X-ray absorption. Oscillator strengths are also computed and we quantify the multireference nature of the wavefunctions to suggest when approaches based on a single reference would be expected to be successful.

13 pages, 2 figures

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Cited by in corpus (5)

• Machine Learning Configuration Interaction
• Machine learning configuration interaction for ab initio potential energy curves
• Efficient Simulation of Near-Edge X-ray Absorption Fine Structure (NEXAFS) in Density-Functional Theory: Comparison of Core-Level Constraining Approaches
• A benchmark study of core-excited states of organic molecules computed with the generalized active space driven similarity renormalization group
• Explicit core-hole single-particle methods for L- and M- edge X-ray absorption and electron energy-loss spectra