Coordinate scaling of the kinetic energy in pair density functional theory: A Legendre transform approach

Abstract

AbstractWe show that the kinetic energy functional in pair density functional theory is homogeneous of degree 2 with respect to coordinate scaling. Although this result was already derived by Levy and Ziesche using the constrained search method (Levy and Ziesche, J Chem Phys 2001, 115, 9110), we derive our result using the Legendre transform formulation (Ayers et al., J Chem Phys 2006, 124, 054101). The advantage of this approach is that in the Legendre transform functional, the N‐representability problem is solved by the functional. By contrast, in the Levy–Ziesche approach, the computationally impracticable N‐representability constraints have to be imposed separately. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009