Abstract
The time-delayed resonant two-photon ionization method has been used to measure the radiative lifetimes of the v = 0 and 1 levels of the A6Σ+ state of CrH, yielding values of 0.939 ± 0.019 and 1.027 ± 0.066 μs, respectively (1 σ error limits). These measured lifetimes are about 16%-45% longer than those obtained in recent ab initio calculations, a result that is important for modeling of the atmospheric concentration of CrH in the class of substellar objects known as brown dwarfs. Based on these results, it is suggested that the line strengths used to calculate the opacity function used by astronomers should be reduced by a factor of 0.799. In addition, line positions are reported for the 0-0 band of the A6Σ+-X6Σ+ system of the minor isotope 50CrH, along with a least-squares fit of the lines to the standard matrix Hamiltonian.