Photoemission from silver into liquid ammonia

Abstract

We report here part of a detailed study of pulsed photoemission into pure liquid NH3. We find that scavengers and salts are not essential to the detection of photoelectrons in NH3, in contrast to previous measurements in H2O. A six order-of-magnitude range in the quantum yield has been found. Maximum yields are near 10−2 electrons per photon. As previous workers, we find a two-slope response to the yield curve which may be interpreted in terms of two thresholds. We interpret out observations in terms of photoinjection into a band of localized states lying below the conduction band of the NH3. The bottom of the conduction band in NH3 is found to be 0.95 eV below the vacuum. The band of localized states extends approximately 0.4 eV lower. Our analysis does not support either the ″4/2’s″ or the ″5/2′s″ laws relating the yield to the excess energy above threshold.