Improved spectroscopic characterisation of the ground X0+(1Σ+), and lowest excited A0+(3II), B1(3Σ+) and D1(1II) energy states of CdNe complex in a wide range of internuclear separations

J. Koperski; M. Czajkowski

doi:10.1007/s100530050560

2024 Impact factor 1.5

Atomic, Molecular, Optical and Plasma Physics

Eur. Phys. J. D 10, 363-377 (2000)
https://doi.org/10.1007/s100530050560

Improved spectroscopic characterisation of the ground X0⁺(¹Σ⁺), and lowest excited A0⁺(³II), B1(³Σ⁺) and D1(¹II) energy states of CdNe complex in a wide range of internuclear separations

J. Koperski¹ and M. Czajkowski²

¹ Instytut Fizyki, Uniwersytet Jagielloński, ul. Reymonta 4, 30-059 Kraków, Poland
² Department of Physics, University of Windsor, Windsor, Ontario, N9B 3P4, Canada

Received: 26 July 1999
Revised: 29 October 1999
Published online: 15 June 2000

Abstract

A first-time observed $A0^+_{v'=1}\rightarrow X0^+$ fluorescence as well as $D1_{v'=1}\rightarrow X0^+$ fluorescence, and $A0^+_{v'}\leftarrow X0^+_{v^{\prime\prime}=0,1,2}$ , $B1_{v'}\leftarrow X0^+_{v^{\prime\prime}=0,1,2}$ and $D1_{v'}\leftarrow X0^+_{v^{\prime\prime}=0,1}$ excitation spectra of the CdNe van der Waals molecule have been recorded in the experiment of a continuous supersonic molecular beam crossed with a pulsed dye laser beam. A rigorous, improved analysis based on complete and simultaneous theoretical simulation of bound-free and bound-bound parts of the spectra is presented. Several controversies concerning interpretation of the $B1(^3\Sigma^+)\leftarrow X0^+(^1\Sigma^+)$ transition and determination of the CdNe ground state dissociation energy is explained and new approaches are postulated. The analysis indicates that a Morse function combined with an adequate term describing a long-range approximation represents the potential energy curve of the $A0^+(^3\Pi)$ , $B1(^3\Sigma^+)$ , $D1(^1\Pi)$ and $X0^+(^1\Sigma^+)$ states below the dissociation limit. In the simulation of the $A0^+(^3\Pi)\rightarrow X0^+(^1\Sigma^+)$ and $D1(^1\Pi)\rightarrow X0^+(^1\Sigma^+)$ bound-free spectra the Morse potential was found to be a good representation of the repulsive wall of the ground-state PE curve above the dissociation limit, over the internuclear separation range of $R=3.15{-}3.75 { \AA}$ . All spectroscopic characteristics for the B1 and $X0^+$ as well as for the $A0^+$ and D1 states obtained in this work are compared with those of other experiments and theoretical calculations.