Subject: SPARTAN'S pBP DFT

From: "E. Lewars" <[email-masked]>
Date: Sat, 29 Aug 1998 12:16:53 -0400 (EDT)

Sat,1998 Aug 29

Hello, Alan Shusterman asked about refs for Spartan's pBP method.
I have a little info' on this from Wavefunction.

>From:  IN%"[email-masked]"   28 August 1998
>To:     IN%"[email-masked]"
>Subj:   SPARTAN: pBP86 reference

>In early July I asked whether anyone has a reference to the "pBP" =
>method. I still don't have an exact reference, but I may have come =
>closer...
>
>Wavefunction recently sent me some papers concerning DFT methods, =
>including one that describes the "use" (but not the implementation) =
>of the pBP86 method. This reference is F. Liangyou and T. Ziegler, =
>J Chem Phys, 94(9), 6057-6063 (1991).
>
>The most interesting paragraph is found on the first page of the =
>article, which states:
>
>"Up to date, most nonlocal calculations have been based on a =
>perturbative approach in which the gradient terms are evaluated =
>from a density generated by local self-consistent (SCF) =
>calculations."
>
>Unfortunately, no references are given. Later on, under the section =
>"VI. Bond Lengths" It is stated that:
>
>"Becke has used the perturbative nonlocal (NL-P) approach (6b) to =
>calculate bond distances for several homonuclear diatomics."
>
>Ref 6b is A.D. Becke, ACS Symposium Series 1989, Number 394 (ACS, =
>Washington DC 1989)
>
>I don't have this monograph, however, so I can't verify whether the =
>cited article describes the "pBP" approach or not. This is as close =
>as I have come to tracking this issue down. If anyone does have =
>this article, I'd be grateful for a copy.
>
>Alan
>
>-----------------
>Alan Shusterman
>Department of Chemistry
>Reed College
>Portland, OR
>www.reed.edu/~alan
===============
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 From Wayne Huang of Wavefunction:
1998 Aug

  Spartans pBP method is closest to (of the Gaussian-type methods) B88-P86
(non-hybrid) functional combination.
  Use of post-SCF gradient corrections has been incorporated in several DFT
programs (e.g. ADF, DGauss, DMol). Was typical before Gaussian implemented a
hybrid method in 1992.
 See book on Spartan's DFT by Hehre and Lou.

  The DN* should be close to 6-311+G* and DN** to 6-311++G**.
  We do not have scaling factors [for freqs, ZPE]. However, pBP underestimates
vib. freqs by a few percent (hardly beyond 5%). For heavier atoms, especially
metals, with freqs < 500 cm-1, might underestimate by 5-10%.
                                        [I have some scaling factors
  [email-masked]                      I worked out myself--EL]
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  E. Lewars
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