In Part I, we develop an exact formal variational principle for the ground-state energy, in which the density tz(r) is the variable function

2002

In Part I, we develop an exact formal variational principle for the ground-state energy, in which the density tz(r) is the variable function

2002

- ' ' &~ IJRING the last decade there has been considerable progress homogeneous in understanding interacting electron the properties of a gas. ' The point of view has been, in general, to regard the electrons as similar to a collection of noninteracting particles with the important additional concept of collective excitations
- This paper deals with the ground state of an interacting electron gas in an external potential v(r)
- In Part I, we develop an exact formal variational principle for the ground-state energy, in which the density tz(r) is the variable function. Into this principle enters a universal functional PLtr(r)), which applies to all electronic systems in their ground state no matter what the external potential is
- The expansion coeKcients are again expressible in terms of the exact ground-state energy and the exact linear, quadratic, etc. , electric response functions of a uniform electron gas to an external potential w(r)
- We collect some results of existing calculations referring to the uniform electron gas which are useful for our present purposes
- Regardless of the outcome of this test, it is hoped that the considerations of this paper shed some new light on the problem of the inhomogeneous electron gas and may suggest further developments