Knowledge Bank

The $KrF B\to X$ emission spectrum near 2500 {\AA} is studied at pressures between 1 and 500 Torr using high-frequency electrical excitation of Kr and appropriate fluorides. The data yield a limiting high-pressure spectrum which agrees with results of a previous analysis, thus supporting the contention that the ``fine structure” in some published spectra is a manifestation of superradiance in this bound-free transition. Accordingly the weaker, longer wavelength peak in the laser spectrum is due to lasing from $v\prime =1$. The transformation from the low- to high-pressure spectrum is reproduced in computer simulated spectra, from which may be deduced information about the changing vibrational distributions in the excited state.