Communications: Explicitly correlated equation-of-motion coupled cluster method for ionized states

Abstract

The ionization potential equation-of-motion (IP-EOM) method, based on linear explicitly correlated coupled cluster singles and doubles theory [CCSD(F12)] is reported. Numerical tests have shown that the present IP-EOM-CCSD(F12) method provides vertical IPs accurate to 0.05 eV compared to those in the complete basis set limit. The corresponding error in vertical IP of 2s shells does not exceed 0.1 eV. © 2010 American Institute of Physics.