Molecular photoionization cross sections by Stieltjes–Chebyshev moment theory applied to Lanczos pseudospectra

摘要: Stieltjes imaging technique is widely used for the ab initio computation of photoionization cross sections and decay widths. The main problem hampering application standard algorithms in conjunction with high-level methods to polyatomic molecules requirement full diagonalization excessively large Hamiltonian matrices. Here we show that bottleneck can be overcome by applying procedure Lanczos pseudospectrum atomic or molecular Hamiltonian. Using helium neon atoms as examples, demonstrate obtained after only a relatively small number iterations Stieltjes-type calculations essentially without loss accuracy. new applied calculation total section benzene within an approach explicitly taking into account single double electronic excitations. Good agreement experimental results obtained.