Title 



Momentum density and its Fourier transform : relation to the firstorder density matrix and some scaling properties
 
Author 



 
Abstract 



Densityfunctional theory requires knowledge of the kineticenergy density t(r) in terms of the groundstate density rho (r). Of course, the direct route to total kinetic energy is from the momentum density n(p), which in turn is directly related by Fourier transform to the firstorder density matrix gamma (r,r'). Here, an alternative route to calculate the total kinetic energy is explored, via the Fourier transform (n) over tilde (r) of the momentum density n (p). It is shown that (n) over tilde (r) is related to the density matrix gamma through its contracted form integral gamma (r'r,r')dr'=(n) over tilde (r). As examples, bare Coulomb field and harmonic confinement for arbitrary numbers of closed shells are treated. Finally, a localized potential V(r) embedded in an initially uniform electron gas is considered, but now to low order in a perturbation series in V(r).   
Language 



English
 
Source (journal) 



Physical review : A : atomic, molecular and optical physics.  Lancaster, Pa, 1990  2015  
Publication 



Lancaster, Pa : 2001
 
ISSN 



10941622 [online]
10502947 [print]
 
Volume/pages 



64:4(2001), p. 16
 
Article Reference 



042509
 
ISI 



000171609900049
 
Medium 



Eonly publicatie
 
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