The densities in diffuse and translucent molecular clouds: estimates from observations of C${}_2$ and from 3-dimensional extinction maps

David A. Neufeld, Daniel E. Welty, Alexei V. Ivlev +7

Newly-computed collisional rate coefficients for the excitation of C${}_2$ in collisions with H${}_2$, presented recently by Najar and Kalugina (2020), are significantly larger than th…