Direct potential fit analysis of the X 1Σg+ state of Rb2: Nothing else will do!
- 22 August 2000
- journal article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 113 (8), 3067-3076
- https://doi.org/10.1063/1.1286979
Abstract
High resolution A-X emission data involving vibrational levels of the ground electronic state up to spanning 99.8% of the potential well, have been acquired for three isotopomers of While a good fit to the 12 148 transition frequencies (with uncertainties ±0.001 cm−1) is obtained from an unconstrained combined-isotopomer Dunham-type analysis, it requires a large number (62) of expansion parameters, and the resulting empirical centrifugal distortion constants (CDCs) are unreliable for extrapolation to higher-J. Moreover, Dunham expansion fits using constrained theoretical values of the first six CDCs (up to fail to properly represent the data, as even higher-order CDCs are required. However, a direct fit of these data to an analytical “modified Lennard-Jones” potential energy function involving only 16 fitted parameters yields essentially the same quality of fit as did the unconstrained Dunham fit, and should be reliable for extrapolation to arbitrarily high J. This potential form incorporates the proper asymptotic behavior of the potential, and is constrained to have the theoretically predicted dispersion coefficient. Although the dataset involves the three isotopomers and none of the present analyses was able to determine any Born–Oppenheimer breakdown effects.
Keywords
This publication has 47 references indexed in Scilit:
- Cold Rubidium Molecules Formed in a Magneto-Optical TrapPhysical Review Letters, 2000
- A “modified Lennard-Jones oscillator” model for diatom potential functionsThe Journal of Chemical Physics, 2000
- Ultracold scattering properties of the short-lived Rb isotopesPhysical Review A, 1999
- Dipolar decay in two recent Bose-Einstein condensation experimentsPhysical Review A, 1996
- Near-dissociation expansions and dissociation energies for Mg+–(rare gas) bimersThe Journal of Chemical Physics, 1994
- Dispersion coefficients for alkali-metal dimersPhysical Review A, 1994
- Centrifugal distortion constants for diatomic molecules: an improved computational methodJournal of Physics B: Atomic and Molecular Physics, 1981
- Heterodyne measurements of 12C18O, 13C16O, and 13C18 O laser frequencies; mass dependence of Dunham coefficientsOptics Communications, 1974
- Über einige Potentialkurven des QuecksilberhydridsThe European Physical Journal A, 1933
- Zur Berechnung von Potentialkurven f r zweiatomige Molek le mit Hilfe von SpektraltermenThe European Physical Journal A, 1932