Long-Range Interactions and the Oscillator Strength for the 1 1 u , 1 0 + u <-- X 1 0 + g Transitions in Zn 2
M.K. Kubkowska, T.M. Szczęśniak and T. Grycuk
Institute of Experimental Physics, Warsaw University Hoża 69, 00-681 Warsaw, Poland
Full Text PDF
Received: February 17, 2004
The interaction potentials for Zn 2 electronic states 1 1 u and 1 0 u + correlated with (4 1 P1+4 1 S0) asymptote in the long-range region (10--25)A and the oscillator strength f for the absorption transition to these states are derived experimentally from a careful analysis of the self-broadened resonance 213.8nm line of Zn. It is found that although the interatomic interactions at so long distances are dominated by resonance potential of the form C 3 /R 3 resulting in the Lorentzian line shape, the parameter C 3 and thus f value significantly decrease with R decreasing. This effect proved to be a linear function of R -1 yielding the oscillator strength for the considered line f 0 =1.456±0.010 from R-->&infty; extrapolation. This value seems to be the most accurate experimental result as yet and shows that the best theoretical values for this quantity are overestimated. It is suggested that the long-range behaviour of the potential energy curves observed here for the first time represents the effective potentials including dominating resonance interactions and a possible slight contribution of the dispersion interactions as well as the R-dependent spin--orbit interaction.
DOI: 10.12693/APhysPolA.105.317
PACS numbers: 32.70.--n, 32.70.Cs, 32.70.Jz, 33.70.--w, 34.20.--b