Intersystem crossing rates of pentacene in naphthalene at 1.9 K following single-mode laser excitation

The rates of nonradiativ decay and the spectra of pentacene in naphthalene are reported. The experiments were carried out at 1.9 K using a single-mode dye laser. The results in the naphthalene host are consistent with our earlier observation of transients in the p-terphenyl host, and suggest a slow rate for intersystem crossing in the molecule