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Photoionization cross sections with optimized orbital exponents within the complex basis function method
Author(s) -
Morita Masato,
Yabushita Satoshi
Publication year - 2008
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.20966
Subject(s) - polarizability , basis function , photoionization , wave function , atomic orbital , basis (linear algebra) , dipole , atom (system on chip) , physics , sto ng basis sets , scaling , quantum mechanics , gaussian , electron , atomic physics , nonlinear system , chemistry , statistical physics , mathematics , linear combination of atomic orbitals , ionization , geometry , molecule , ion , computer science , embedded system
Abstract We show a new direction to expand the applicability of the complex basis function method for calculating photoionization cross sections through the imaginary part of the frequency‐dependent polarizability. Based on the variational stability of the frequency‐dependent polarizability, we made nonlinear optimizations of complex orbital exponents in basis functions representing continuum wave functions, and obtained fairly accurate results for H atom with only one or two complex basis functions particularly with dipole velocity gauge. Results were almost independent of whether Slater‐type or Gaussian‐type orbitals are used, implying the applicability to general many electron problems. The method was also applied to the 1 S (1s) 2 → 1 P (1s) 1 (kp) 1 cross section of He atom and the optimized complex orbital exponents were related to those of H atom through the scaling property. The nonlinear optimizations have converged smoothly and the cross sections were in excellent agreement with experiment throughout wide photon energies, which suggest the effectiveness of the approach for many‐electron systems. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2008