Charge transfer and association of protons colliding with potassium from very low to intermediate energies

The nonradiative charge-transfer process for H+ + K(4s) collision is investigated using the quantum-mechanical molecular-orbital close-coupling method for collision energies from 1 eV to 10 keV. The radiative-decay and radiative charge transfer cross sections are calculated using the optical potential approach and the fully quantal method, respectively, for the energy range of 10(-5)-10 eV. The radiative-association cross sections are obtained by subtracting the radiative charge-transfer part from total radiative-decay cross sections. The relevant molecular data are calculated from the multireference single-and double-excitation configuration interaction approach. The nonradiative charge transfer is the dominant mechanism at energies above 2 eV, whereas the radiative charge transfer becomes primary in the low-energy region of E < 1.5 eV. The present radiative-decay cross sections disagree with the calculations of Watanabe et al. [Phys. Rev. A 66, 044701 (2002)]. The total charge-transfer rate coefficient is obtained in the temperature range of 1-20 000 K.