title: Hartree-Fock orbitals for complex-scaled configuration interaction calculation of highly excited Feshbach resonances.
abstract: We examine a complex-scaled configuration interaction [(CS)CI] for highly excited Feshbach resonances, where we study the 2s(2) resonance of helium as a test case. Sizable full-CI calculations are reduced by using a correctly defined minimum active space. We compare the convergence of the minimum active space for conventional Hartree-Fock (HF) orbitals obtained as solutions to Hermitian HF equations, to the convergence of minimum active space for complex orbitals obtained as solutions to complex-scaled HF equations. Ground-state optimized orbitals are compared to a simple modification of the HF method using the excited-state mean-field potential.
authors.affiliation: Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam.2, 166 10 Prague 6, Czech Republic. petra.zdanska@uochb.cas.cz
authors.forename: Petra R
authors.initials: PR
authors.lastname: Zdánská
authors.forename: Nimrod
authors.initials: N
authors.lastname: Moiseyev