NEW SINGLET RYDBERG STATES OF THE NH(ND) RADICAL IN THE ENERGY-RANGE 92000-100000 CM-1 CHARACTERIZED BY RESONANCE ENHANCED MULTIPHOTON IONIZATION-PHOTOELECTRON SPECTROSCOPY
Sg. Clement et al., NEW SINGLET RYDBERG STATES OF THE NH(ND) RADICAL IN THE ENERGY-RANGE 92000-100000 CM-1 CHARACTERIZED BY RESONANCE ENHANCED MULTIPHOTON IONIZATION-PHOTOELECTRON SPECTROSCOPY, The Journal of chemical physics, 96(7), 1992, pp. 4963-4973
Two new singlet excited electronic states of the imidogen radical have
been characterized through (i) analysis of the two photon resonance e
nhancements they provide in the wavelength resolved multiphoton ioniza
tion spectrum of a (1)DELTA state NH (ND) radicals and (ii) measuremen
ts of the kinetic energy of the photoelectrons accompanying the multip
hoton ionization process. The i (1)PI state is shown to involve a ...3
-sigma(2)1-pi(1) ion core and a Rydberg electron of mixed 3p-sigma/3d-
sigma character. The zero-point level of this state in ND exhibits an
anomalously large LAMBDA-doubling. Photoelectron kinetic energy releas
e measurements reveal that 2 + 1 resonance enhanced multiphoton ioniza
tion via the j (1)DELTA state of NH leads to population of a range of
upsilon+ vibrational levels in the ground state ion and, importantly,
to a substantial population of electronically excited B (2)DELTA state
ions. We conclude that the j (1)DELTA state of NH (ND) also involves
a mixture of configurations, including ...3-sigma(2)1-pi(1)3d-pi(1) an
d the core excited configuration ...3-sigma(1)1-pi(2)3s-sigma(1). All
observed vibrational levels of this state in both NH and ND show pertu
rbations, some of which have proved amenable to analysis.