Simulating weak-field attosecond processes with a Lanczos reduced basis approach to time-dependent equation-of-motion coupled-cluster theory

A time-dependent equation of motion coupled cluster singles and doubles (TD-EOM-CCSD) method is implemented, which uses a reduced basis calculated with the asymmetric band Lanczos algorithm. The approach used to study weak-field processes in small molecules induced by ultrashort valence pump core probe pulses. We assess reliability procedure comparing TD-EOM-CCSD absorption spectra obtained from coupled-cluster (TDCCSD) observe that spectral features can be reproduced for several molecules, at much lower computational times. discuss how multiphoton symmetry handled general core-valence separation (CVS) projection technique. also model transient an attosecond X-ray pulse glycine molecule.