Abstract
A new metastable state in mercury has been observed at an energy of 10.530 eV. It is assigned as 5d96s2(2D32/)6p12/(3/21/2)2 and its lifetime is estimated to be approximately 200 mu s. A novel technique has been used to differentiate this new metastable state from the other, lower-lying, metastable states of mercury, and high-resolution electron impact has been used to measure its excitation function, which displays resonance structure. A mechanism is described by which atoms in this metastable state de-excite at the detecting surface.