Non-LTE analysis of the formation of KI lines in the spectra of A-K stars

The non-LTE formation of KI lines in the spectra of A-K stars is analyzed. The computations are based on a 36-level model of the neutral potassium ato m for blanketed LTE Kurucz model atmospheres with T-eff = 4000-10000 K, log g = 0.0-4.5, and [M/H] = (0.0)-(-2.0). The KI atoms in the atmospheres of these stars are in states of moderate and strong "over-recombination." A nu mber of atomic parameters are refined using the profiles and equivalent wid ths of five lines in the solar spectrum. The classical van der Waals dampin g constants must be increased by factors of 2-60 to fit the observed profil es. The non-LTE solar potassium abundance-loge (K) = 5.14-corresponds to th e meteoritic abundance. Non-LTE corrections to the potassium abundance are important and equal to -0.4...-0.7 dex for the lambda 7699 Angstrom, line a nd -0.15...-0.3 dex for the lambda lambda 12522, 12432, and 11769 Angstrom lines. (C) 2000 MAIK "Nauka/Interperiodica".