RANGE RELAXATION .I. CALCULATION OF GROUND STATE ENERGY CURVES

The first of three integral forms of the quantum mechanical variational principle is described and a method introduced for the simultaneous optimisation of the whole of a molecular energy curve, or surface, generated for some adiabatic change. Dimensionless parameters in the wavefunction are expressed as functions of the coordinates and the integral of the energy over the whole surface is minimised with respect to variations in these functions. An integral form of the Virial Theorem is proposed as a test that the wavefunction is in scale for the whole range. A preliminary application is made to the H2+, H2 and He2 systems. © 1969 Springer-Verlag.