Many-body theory of the ionization energies of CH3-, SiH3-, and GeH3-

Abstract

Electron propagator theory is used to calculate the vertical ionization energies of CH/sub 3//sup -/, SiH/sub 3//sup -/, and GeH/sub 3//sup -/. Basis set augmentations are made until changes in the computational results are small. Adiabatic ionization energies are obtained via many-body-perturbation-theory calculations on the neutral potential energy surface. The adiabatic values are in excellent agreement with photoelectron spectroscopy measurements on CH/sub 3//sup -/ and SiH/sub 3//sup -/. Comparable calculations are made for GeH/sub 3//sup -/. Calculated vertical ionization energies are 0.51 eV for CH/sub 3//sup -/, 1.79 eV for SiH/sub 3//sup -/, and 2.01 eV for GeH/sub 3//sup -/; adiabatic counterparts are 0.19, 1.31, and 1.39 eV, respectively. Calculations employing effective core potentials for SiH/sub 3//sup -/ and GeH/sub 3//sup -/ agree closely with all-electron results. Vertical ionization energies employing these techniques are 1.88 eV for SiH/sub 3//sup -/ and 1.97 eV for GeH/sub 3//sup -/. Adiabatic effective core potential results are 1.46 eV for SiH/sub 3//sup -/ and 1.49 eV for GeH/sub 3//sup -/.