We present some of our contributions to the advancement of explicitly time-dependent coupled-cluster theory towards the efficient computation of linear absorption spectra of molecular systems. Our newly developed explicitly time-dependent EOM-CC (TD-EOM-CC) formalism based on the propagation of the CC dipole function possesses great potential for the efficient computation of linear absorption spectra over arbitrarily wide energy windows. This approach introduces no approximations and requires only half of the computational effort of TD-CC methods based on the propagation of the wave function. The TD-EOM-CC formalism is particularly interesting when dealing with molecular systems with high density-of-states, or if the spectral region of interest spans a large energy range (&gt; 10eV). We perform illustrative calculations of the UV-Vis, NEXAFS, and electronic circular dichroism (ECD) spectra of several molecular species relevant to the study of atmospheric chemistry and astrochemistry. Furthermore, we exploit extrapolation techniques based on Padé approximants. These techniques are shown to significantly reduce the computational effort required to simulate NEXAFS spectra.

Broadband absorption spectra from time-dependent coupled-cluster theory

254th National Meeting (2017)

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