Author:
Nandi D,Jana I,Ramaprasad V
Abstract
Synopsis
Formation of O− and
O
2
−
ions via DEA to a supersonic jet of O2 having weakly bound van der Waals clusters is reported. The ion-yields show three peaks near 7, 11 and 16 eV electron energies where the 7 eV peak arises from the 2Π
u
state of
O
2
−
. The 11 and 16 eV peaks are ascribed to two resonance states
2
Σ
g
+
and
2
Σ
u
+
respectively, through a violation of σ−
selection rule. Ar was used as a refrigerant carrier gas and cross-section dependence of the two new peaks on the proportion of carrier gas used is experimentally observed, eventually leading to an optimum O2 : Ar ratio.
Subject
General Physics and Astronomy