title: Excited state X-ray absorption spectroscopy: Probing both electronic and structural dynamics.
abstract: We investigate the sensitivity of X-ray absorption spectra, simulated using a general method, to properties of molecular excited states. Recently, Averbukh and co-workers [M. Ruberti et al., J. Chem. Phys. 140, 184107 (2014)] introduced an efficient and accurate L2method for the calculation of excited state valence photoionization cross-sections based on the application of Stieltjes imaging to the Lanczos pseudo-spectrum of the algebraic diagrammatic construction (ADC) representation of the electronic Hamiltonian. In this paper, we report an extension of this method to the calculation of excited state core photoionization cross-sections. We demonstrate that, at the ADC(2)x level of theory, ground state X-ray absorption spectra may be accurately reproduced, validating the method. Significantly, the calculated X-ray absorption spectra of the excited states are found to be sensitive to both geometric distortions (structural dynamics) and the electronic character (electronic dynamics) of the initial state, suggesting that core excitation spectroscopies will be useful probes of excited state non-adiabatic dynamics. We anticipate that the method presented here can be combined with ab initio molecular dynamics calculations to simulate the time-resolved X-ray spectroscopy of excited state molecular wavepacket dynamics.
authors: Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada.
authors: Simon P
authors: SP
authors: Neville
authors: Department of Physics, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom.
authors: Vitali
authors: V
authors: Averbukh
authors: Department of Physics, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom.
authors: Marco
authors: M
authors: Ruberti
authors: Department of Physics, Imperial College London, South Kensington Campus, London, SW7 2AZ, United Kingdom.
authors: Renjie
authors: R
authors: Yun
authors: Max-Born Institute, Max-Born-Strasse 2A, D-12489 Berlin, Germany.
authors: Serguei
authors: S
authors: Patchkovskii
authors: Ecole Polytechnique Fédérale de Lausanne, Laboratoire de Spectroscopie Ultrarapide, Faculté des Sciences de Base, ISIC, Lausanne CH-1015, Switzerland.
authors: Majed
authors: M
authors: Chergui
authors: Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada.
authors: Albert
authors: A
authors: Stolow
authors: Department of Chemistry, University of Ottawa, 10 Marie Curie, Ottawa, Ontario, K1N 6N5, Canada.
authors: Michael S
authors: MS
authors: Schuurman