Subject: CCL: Pd-ethylene cluster with G98

From: Jesus Rodriguez-Otero <qftjesus:at:usc.es>
Date: Thu, 27 Nov 2003 09:13:51 +0100

Hi netters,

I am comparing the performance of HF, DFT/B3LYP anda MP2 with Gaussian98 in 
a simple
calculation of a cluster formed by two Pd atoms and ethylene. To my 
surprise, b3lyp is
much slower than HF or MP2; cpu times are

hf: 	3 min. 21 s.
b3lyp:	1 h. 5 min.
mp2:	8 min. 28 s.

P-IV running LINUX

this is my input file:
------------------------------------------------------------------------------------
%chk=pd2etepa.chk
# hf/lanl2mb opt(z-matrix,maxcyc=60) scf(qc,maxcyc=500)

Title Card Required

0  1
  Pd
  Pd                 1        2.750872
  C                  1              B1    2              A1
  C                  3              B2    1              A2    2 
   D1
  H                  4              B3    3              A3    1 
   D2
  H                  3              B4    4              A4    5 
   D3
  H                  4              B5    3              A5    6 
   D4
  H                  3              B6    4              A6    7 
   D5

    B1             2.408742
    B2             1.354929
    B3             1.070182
    B4             1.070143
    B5             1.070035
    B6             1.069670
    A1            76.672064
    A2           107.368541
    A3           120.230124
    A4           119.863439
    A5           119.916731
    A6           120.275618
    D1             1.099106
    D2            90.171155
    D3             0.053786
    D4          -179.938316
    D5             0.015838
-------------------------------------------------------------------------------------------

Is this normal?
Can dft performance be improved?

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Jeszs Rodrmguez-Otero
Departamento de Qummica Fmsica, Facultade de Qummica
Universidade de Santiago
15782 Santiago de Compostela, (Spain)
Phone: (+34)-981563100 ext 14436, Fax: (+34)-981595012
qftjesus:at:usc.es
http://web.usc.es/~qftjesus/index.html