Cc. Arnold et Dm. Neumark, STUDY OF IN2P IN2P- AND INP2/INP2- USING NEGATIVE-ION ZERO ELECTRON KINETIC-ENERGY SPECTROSCOPY/, Canadian journal of physics, 72(11-12), 1994, pp. 1322-1335
The zero electron kinetic energy (ZEKE) spectra of In2P- and InP2- are
presented and compared to their previously obtained photoelectron spe
ctra (PES) as well as ab initio calculations on analogous species. The
threshold spectra, which give high-accuracy electron affinities of 2.
400 +/- 0.001 eV for In2P and 1.617 +/- 0.001 eV for InP2, show well-r
esolved vibrational structure in the transitions from the ground anion
states to the various neutral states. The ZEKE spectrum of In2P- exhi
bits a fairly extended, 47 cm(-1) progression that we assign to the sy
mmetric bend (upsilon(2)) in the ground B-2(1) neutral state. There is
also a 204 cm(-1) progression that we assign to the symmetric stretch
. The InP2- ZEKE spectrum shows transitions to two electronic states o
f the neutral. For the ground state, the symmetric stretch mode is the
most active in the spectrum, whereas in the excited state, the symmet
ric bend mode is most active. The InP2 ground-slate symmetric stretch
frequency is 190 cm(-1), and the excited-state symmetric bend frequenc
y is 287 cm(-1). An anion ground-state frequency is determined to be 2
27 cm(-1). The term energy of the excited state is determined to be 1.
280 +/- 0.001 eV. Based on molecular orbital arguments, these frequenc
ies suggest a B-2(2) ground InP2 state, a (2)A(1) first excited state,
and a (1)A(1) anion ground state.