Mt. Zanni et al., CHARACTERIZATION OF THE I-2(-) ANION GROUND-STATE USING CONVENTIONAL AND FEMTOSECOND PHOTOELECTRON-SPECTROSCOPY, The Journal of chemical physics, 107(19), 1997, pp. 7613-7619
The (X) over tilde (2) Sigma(u)(+) state of the I-2(-) anion has been
fit to a Morse potential using data from two techniques: conventional
and femtosecond photoelectron spectroscopy (FPES). Conventional photoe
lectron spectroscopy is used to determine the adiabatic electron affin
ity of I-2 as well as the well depth and equilibrium nuclear geometry
of I-2(-). In the FPES experiment, the pump pulse induces coherent nuc
lear motion on the ground state of I-2(-) by resonant impulsive stimul
ated Raman scattering (RISRS), and the vibrational frequency of the an
ion is determined from the resulting oscillatory structure in the time
-dependent photoelectron spectra. We find the electron affinity (EA) o
f I-2 to be 2.524 +/- 0.005 eV, the well depth (D-e) for I-2(-) to be
1.014 +/- 0.005 eV, the equilibrium internuclear separation (R-e) to b
e 3.205 +/- 0.005 Angstrom, and the vibrational frequency to be 110 +/
- 2 cm(-1). These values for the I-2(-) potential parameters differ si
gnificantly from previous results. (C) 1997 American Institute of Phys
ics.