SEMIEMPIRICAL DETERMINATION OF THE VIBRONIC CONSTANTS OF DIATOMIC MOLECULES. OPTIMAL SETS OF CONSTANTS a3 SIGMA g + , e3 SIGMA u + , d3 PI u + or minus , AND f3 SIGMA u + OF STATES OF H2.

The possibility of describing the vibronic electron levels of diatomic molecules by means of a limited set of molecular constants is investigated. For the example of the low triplet states of H//2, it is shown that, in determining the set of vibronic constants of the given electron state and their covariance matrix, account must be taken of the specific features of the physical problem for which these constants are to be used. The optimal sets of constants obtained are significantly different from those in the literature. The reasons for the discrepancy are discussed.