Short-range correlation in the uniform electron gas: Extended Overhauser model - art. no. 155102

We use the two-electron wave functions (geminals) and the simple screened C oulomb potential proposed by Overhauser [Can. J. Phys. 73, 683 (1995)] to c ompute the pair-distribution function g(r) for a uniform electron gas, find ing the exact g(0) for this model and extending the results from g(0) to g( r), We find that the short-range (r<r(s)) part of this g(r) is in excellent agreement with quantum Monte Carlo simulations for a wide ran-e of electro n densities. We are thus able to estimate the value of the second-order (r( 2)) coefficient of the small interelectronic-distance expansion of the pair -distribution function. The coefficients of the small-r expansion of the sp in-resolved g(<sigma>sigma')(r) have density or r(s) dependencies which we parametrize in a way that makes it easy to find their coupling-constant ave rages. Their spin-polarization or zeta dependencies are estimated from a pr oposed spin-scaling relation.