The energy of a negative ion inside a non-polar liquid is calculated by mea
ns of a simple one parameter trial wave function for the extra electron. Th
e general relation connecting the threshold for gas phase photodetachment a
nd photoinjection into the conduction level of the liquid yields a self con
sistent equation for the binding energy of the lone electron. The energy of
O-2(-); in different solvents is calculated and compared with experimental
data. (C) 1999 Elsevier Science B.V. All rights reserved.