Our previous calculation of the excited atom population [T. Fujimoto, K. Sawada, and K. Takahata, J. Appl. Phys.66, 2315 (1989)] is revised on the basis of new assessment of the cross sections for excitation from atomic hydrogen and dissociative excitation from molecular hydrogen. The effective ionization rate of molecular hydrogen is also calculated by the method of the collisional‐radiative model. Its ratio to the Balmer &agr; photon emission rate is higher than that for the atomic hydrogen case by more than one order of magnitude.