B³Π(0⁺) states of IF, ICI and IBr. Part 1 —Calculation of the RKR turning points and Franck–Condon factors for the B–X Systems

Abstract

Values of the spectroscopic constants for the B3rI(O+) -X'Z+ systems of IF, IC1 and IBr have been evaluated and used to determine the RKR turning points for the B311(O+) and X'C+ states of the iodine monohalides. The RKR potential functions have been used to calculate r-centroids and Franck-Condon factors for the B-X systems.

Combined experimental/theoretical investigation of the He+ICl interactions. I. Rovibronic spectrum of He⋯ICl complexes in the ICl B–X, 3–0 region

“…The ICl potential, V ICl (r), is obtained from a spline interpolation of the RKR turning points of Clyne and McDermid 41. The interpolated ICl potential gives vibrational energies for the ICl(B,vЈϭ2,3) states of 478.5 and 643.4 cm Ϫ1 , which are in good agreement with the experimental values of 480.4 and 643.9 cm Ϫ1 .…”

Spectroscopic observation of the preferentially stabilized, linear He⋯ICl(X 1Σ+) complex

“…A combination of 600 and 610 nm long-pass filters was placed before the photomultiplier tube to block laser scatter and to transmit fluorescence in the ICl B→X Franck-Condon window. 21 Two boxcar gated integrators were used to record the intensity of the LIF signal as a function of laser excitation wavelength. One integration gate with a width of 500 ns was set at long time, ϳ100 ns after the excitation laser, to collect fluorescence from longlived excited state species.…”

“…The fluorescence excitation spectra of the He¯ICl complexes are most easily recorded in the ICl B -X, 3-0 spectral region since the Franck-Condon factors for the 3-0 transitions are the largest within the B -X region that can be accessed. 21 Furthermore, while the ICl B -X, vЈ-0 monomer vibrational bands have energies that to some extent overlap the He¯ICl spectral features, the curve crossing of the purely dissociative ICl(Z1) state with the ICl(B 3 ⌸ 0ϩ ) potential well near the vЈϭ3 level greatly reduces the excited state lifetime of the ICl(B,vЈϭ3) rotational states and the fluorescence quantum yield when promoting ICl molecules to these states. 21,26 -28 The LIF spectra recorded in the ICl B -X, 3-0 spectral region shown in Figure 1 were collected using a helium backing pressure of 115 psi with the laser axis intersecting the supersonic expansion at x/dϭ12.5.…”

Laser‐Induced Fluorescence: Electronically Excited States of Small Molecules

“…For many molecules, such as the halogens (Coxon, 1971), interhalogens (Clyne and McDermid, 1976a), OH (Crosley and Lengel, 1975;Chidsey and Crosley, 1980), CN (Rao and Lakshman, 1972), etc., accurate RKR potential energy curves and the derived Franck-Condon densities are now available over considerable ranges of u' and u". The accuracy of this approach is dependent upon the availability of reliable Franck-Condon densities.…”