Four‐Dimensional Electron Density Function

The energy, dipole moment, and many other properties of an atom or molecule can be calculated if the pair density matrix, a function of 12 variables, is available. A system is considered for calculating N electrons by four-dimensional electron density functions. The results show that the ground state energy of a systewa of electrons in the field of a set of flxed nuclei can be calculated if the electron density function is known sufflciently accurately, not only as a function of the spatial coordinates x, y, z but also of the parameter Z (0 to 1) which measures the scale of the nuclear charges. (N.W.R.)