Column densities of interstellar molecular hydrogen

Equivalent widths of some 50 lines in the 0-0 to 5-0 Lyman bands of H2 are reported in the spectra of 28 stars. Curves of growth are given and column densities for levels from J = 0 to J = 5 are tabulated, with a few values and upper limits for N(6) and N(7), together with values for b, the velocity spread parameter. In three Orion stars and in rho Leo pairs of components are detected, the difference in radial velocity is determined, and column densities are measured or estimated; tentative identifications are made with the components observed by Hobbs (1969) in the Na D-lines. Column densities for HD are given for 13 stars. Upper limits for column densities in the first and second vibrational levels are listed for several stars; the ratio of N(J = 0) in the v double prime = 1 level to that in the ground vibrational level is less than 2.4 x 10 to the minus 8th power in zeta Oph. Values of a rotational excitation temperature for the higher J levels are given for all the stars. Data are presented which show an apparent increase of velocity dispersion with J for a number of stars, as measured both from the curves of growth and from line widths.