Subject: CCL: Question about G94 DFT calculations

From: Shubin Liu <[email-masked]>
Date: Thu, 11 Dec 1997 10:18:18 -0500 (EST)

Hi, all:

We recently come up to realize some strange error in G94 DFT
calculations. We found that the total energy is NOT equal to
the sum of the kinetic, nuclear-electron attraction, electron-
electron replsion, and nuclear-nuclear repulsion energies, i.e.,
	E = T + Vne + Vee + Vnn
is violated in G94 DFT runs. Could someone please tell us what is
going on in there? Thank you in adavnce!

Have a nice day!

Shubin
 .............................................................................
Shubin Liu

Department of Chemistry		    Email:     [email-masked]
Kenan Hall A207, CB# 3290                      [email-masked]
University of North Carolina	    Home Page: http://www.unc.edu/~shubin 
Chapel Hill, NC 27599-3290	    Tel  :     (919) 962-0150 (Office)
USA                                 Fax  :     (919) 962-2388
 .............................................................................

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From: Shubin Liu <[email-masked]>
Date: Thu, 11 Dec 1997 17:01:28 -0500 (EST)

Hi, all:

Since I posted the question below in CCL, I received several message
which seemingly misunderstood the situation. Sorry that I did not make
things clear enough. I feel necessary to add following two points.

(1) I am sure that Vee component includes the exchange-correlation part,
because it is defined as
	Vee = J + Exc
where J is the classical Coulomb repulsion energy and Exc is the
exchange-correlation energy. 

(2) The second point is that the error in following equality
	 E = T + Vne + Vee + Vnn
is actually very small, often in the third or forth decimal. But it should
not be so, right?! It supposedly should be the exact equation!!!

I am still soliciting answers to this question. Thanx a lot to those of
you who paid the attention and who gave me response.

With best regards!

Shubin
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> going on in there? Thank you in adavnce!
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