TY - JOUR

T1 - Photoionization cross sections of H2+ and H 2 with complex Gaussian-type basis functions optimized for the frequency-dependent polarizabilities

AU - Morita, Masato

AU - Yabushita, Satoshi

PY - 2008/11/15

Y1 - 2008/11/15

N2 - Within the framework of the complex basis function method, the photoionization cross sections of H2+ and H2 were calculated based on the variational principle for the frequency-dependent polarizabilities. In these calculations, complex orbital exponents of Gaussian-type basis functions for the final state continuum wavefunctions were fully optimized for each photon energy with the numerical Newton-Raphson method. In most cases, the use of only one or two complex Gaussian-type basis functions was enough to obtain excellent agreement with previous high precision calculations and available experimental results. However, there were a few cases, in which the use of complex basis functions having various angular momentum quantum numbers was crucial to obtain the accurate results. The behavior of the complex orbital exponents as a function of photon energy was discussed in relation to the scaling relation and the effective charge for photoelectron. The success of this method implies the effectiveness of the optimization of orbital exponents to reduce the number of basis functions and shows the possibility to calculate photoionization cross sections of general molecules using only Gaussian-type basis functions.

AB - Within the framework of the complex basis function method, the photoionization cross sections of H2+ and H2 were calculated based on the variational principle for the frequency-dependent polarizabilities. In these calculations, complex orbital exponents of Gaussian-type basis functions for the final state continuum wavefunctions were fully optimized for each photon energy with the numerical Newton-Raphson method. In most cases, the use of only one or two complex Gaussian-type basis functions was enough to obtain excellent agreement with previous high precision calculations and available experimental results. However, there were a few cases, in which the use of complex basis functions having various angular momentum quantum numbers was crucial to obtain the accurate results. The behavior of the complex orbital exponents as a function of photon energy was discussed in relation to the scaling relation and the effective charge for photoelectron. The success of this method implies the effectiveness of the optimization of orbital exponents to reduce the number of basis functions and shows the possibility to calculate photoionization cross sections of general molecules using only Gaussian-type basis functions.

KW - Complex basis function method

KW - Continuum wavefunction

KW - Newton-Raphson method

KW - Orbital exponent optimization

KW - Photoionization cross section

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U2 - 10.1002/jcc.20992

DO - 10.1002/jcc.20992

M3 - Article

C2 - 18473327

AN - SCOPUS:52649090635

VL - 29

SP - 2471

EP - 2478

JO - Journal of Computational Chemistry

JF - Journal of Computational Chemistry

SN - 0192-8651

IS - 14

ER -