DETERMINING REPULSIVE POTENTIAL CURVES FROM EMISSION CONTINUA: THE $X^{1}\Sigma^{+}{_{g}}$ STATE OF $He_{2}$

Abstract

It is shown that the peak positions of the 600 {\AA} bands of $^{3} He_{2}$ (A $^{1}\Sigma^{+}_{g}\rightarrow X^{1}\Sigma^{+}_{g}$) can be derived from those of $^{4} He_{2}$ if the vibrational numbering adopted in a recent $determination^{1}$ of the A state RKR potential curve is used. Given this A state potential and the 600 {\AA} band spectrum, we developed a least-squares iterative procedure to derive the repulsive X potential in the range $1.3<{R}<$ 2.4 {\AA} ($1.05> {V}>$.02 eV). The result, V(R)=202 exp (--3.88 R) eV, compares favorably with curves derived from elastic scattering data and from theoretical calculations. $^{1}$A.L. Smith and K. W. Chow, J. Chem. Phys. 52, 1010 (1970).