Abstract: The programmed quantum mechanical CI method in Gaussian 82 program, which is publicly recognized, is used in this paper. An ab initio calculation is made, on the basis of using a relatively large basis set 6-31G^**, on the four kinds of configuration formed by the two H₂ molecules. In so doing, the existence of the abnormal structure within the short-range area of the interaction potential curve is confirmed. In this paper, the rules of H₂ molecule bond length changing with the distance between center of mass of two molecules and the corresponding charge redistribution are also reported.

Key words: H₂ molecule, short-range, bond length