Study ofF-Center Formation in KCl on a Picosecond Time Scale

Abstract

We have measured the growth of $F$-band absorption at 532 nm in pure KCl following two-quantum band-gap excitation by a 266-nm pulse. The rise time at $T\approx 25$ K is 11±9 psec. Spectral measurements confirm attribution of the early absorption to $F$ centers. This absorption reflects the generation of new Frenkel defects with the $F$ center created directly in its electronic ground state.