Depolarization rates of resonance lines of Mg, Ca, Sr and Na atoms by collisions with hydrogen atoms

Multipole relaxation and transfer rates due to isotropic collisions with neutral hydrogen are calculated and a general expression for the hyperfine-structured levels is obtained. Evaluation of these rates has been carried out using ab initio potentials. Analytic fits of the temperature dependence of the rates are available for T ranging from 200 K to 10000 K. In the physical conditions commonly assumed for the formation of the NaI resonance lines, our results indicate that the ground state is depolarized for hydrogen densities larger than 10(14) cm(-3).