[molpro-user] different results segmented<->general contractions

Wed Oct 28 18:28:12 GMT 2009

Dear Molpro users,

One of my students has been doing CASSCF excited-state calculations using
Molpro, and noticed differences in the results if she ticks or not ticks the
"optimized general contractions" box when taking correlation consistent basis
sets from the EMSL basis set site. I know that this option just removes from the
general contractions the primitive that is also used uncontracted, to make the
basis set work more efficiently with programs that support only segmented
contractions. So ticking or not ticking this box should yield the same basis
set, and therefore the results should be the same. Or am I missing something?

We get the same results if we just compute the CASSCF ground-state energy.
However, when computing excited states, there are significant differences, for
example, for the input example below, the results are:

"optimized general contractions" unselected:

 !MCSCF STATE 1.1 ENERGY             -642.134635362437
 !MCSCF STATE 1.1 DIPOLE MOMENT        -0.32765294     0.92287005     1.17631226
 !MCSCF STATE 2.1 ENERGY             -641.868731948405
 !MCSCF STATE 2.1 DIPOLE MOMENT        -0.96546607    -0.43965941    -0.07105395

"optimized general contractions" selected:
 !MCSCF STATE 1.1 ENERGY             -642.136366749999
 !MCSCF STATE 1.1 DIPOLE MOMENT        -0.32929977     0.81772379     1.14350008
 !MCSCF STATE 2.1 ENERGY             -641.855949809309
 !MCSCF STATE 2.1 DIPOLE MOMENT        -0.80264158    -0.20134531    -0.18076690

The input for the "optimized general contractions" case is:
===================================
 ***,2-keto singlet
 memory,400,m;

 geomtyp=xyz
 geometry={
 8
 posphate group
  P                  0.07854900   -0.05791100   -0.10861500
  O                  1.03411300   -0.52179800   -1.13286600
  O                 -0.99689500   -1.16731000    0.32924700
  H                 -1.66406600   -0.84451300    0.95852600
  O                 -0.90278800    1.17835500   -0.45177200
  H                 -0.43421500    1.96143600   -0.78591300
  O                  0.77406700    0.47094500    1.26445500
  H                  1.65207400    0.07020700    1.38410100
 }

   basis={
  !
  ! HYDROGEN       (5s,2p) -> [3s,2p]
  ! HYDROGEN       (4s,1p) -> [2s,1p]
  ! HYDROGEN       (1s,1p)
  s, H , 13.0100000, 1.9620000, 0.4446000, 0.1220000, 0.029740
  c, 1.3, 0.0196850, 0.1379770, 0.4781480
  c, 4.4, 1
  c, 5.5, 1
  p, H , 0.7270000, 0.141000
  c, 1.1, 1
  c, 2.2, 1
  ! OXYGEN       (10s,5p,2d) -> [4s,3p,2d]
  ! OXYGEN       (9s,4p,1d) -> [3s,2p,1d]
  ! OXYGEN       (1s,1p,1d)
  s, O , 11720.0000000, 1759.0000000, 400.8000000, 113.7000000, 37.0300000,
13.2700000, 5.0250000, 1.0130000, 0.3023000, 0.078960
  c, 1.8, 0.0007100, 0.0054700, 0.0278370, 0.1048000, 0.2830620, 0.4487190,
0.2709520, 0.0154580
  c, 1.8, -0.0001600, -0.0012630, -0.0062670, -0.0257160, -0.0709240,
-0.1654110, -0.1169550, 0.5573680
  c, 9.9, 1
  c, 10.10, 1
  p, O , 17.7000000, 3.8540000, 1.0460000, 0.2753000, 0.068560
  c, 1.3, 0.0430180, 0.2289130, 0.5087280
  c, 4.4, 1
  c, 5.5, 1
  d, O , 1.1850000, 0.332000
  c, 1.1, 1
  c, 2.2, 1
  ! PHOSPHOROUS       (13s,9p,2d) -> [5s,4p,2d]
  ! PHOSPHOROUS       (12s,8p,1d) -> [4s,3p,1d]
  ! PHOSPHOROUS       (1s,1p,1d)
  s, P , 94840.0000000, 14220.0000000, 3236.0000000, 917.1000000, 299.5000000,
108.1000000, 42.1800000, 17.2800000, 4.8580000, 1.8180000, 0.3372000,
0.1232000, 0.04170
  c, 1.11, 0.255509D-03, 0.198193D-02, 0.102760D-01, 0.414823D-01, 0.131984D+00,
0.308662D+00, 0.420647D+00, 0.222878D+00, 0.164035D-01, -0.254255D-02,
0.748050D-03
  c, 1.11, -0.696939D-04, -0.535266D-03, -0.283709D-02, -0.113983D-01,
-0.392929D-01, -0.996364D-01, -0.197983D+00, -0.114860D+00, 0.518595D+00,
0.601847D+00, 0.368612D-01
  c, 1.11, 0.191199D-04, 0.147223D-03, 0.777912D-03, 0.314546D-02, 0.108200D-01,
0.279957D-01, 0.563978D-01, 0.358190D-01, -0.193387D+00, -0.372097D+00,
0.624246D+00  c, 12.12, 1  c, 13.13, 1  p, P , 370.5000000, 87.3300000,
27.5900000, 10.0000000, 3.8250000, 1.4940000, 0.3921000, 0.1186000, 0.03430  c,
1.7, 0.395005D-02, 0.302492D-01, 0.129554D+00, 0.327594D+00, 0.456992D+00,
0.253086D+00, 0.168798D-01  c, 1.7, -0.959832D-03, -0.711177D-02,
-0.327122D-01, -0.795784D-01, -0.135016D+00, -0.910585D-02, 0.537802D+00  c,
8.8, 1  c, 9.9, 1  d, P , 0.3730000, 0.11300  c, 1.1, 1  c, 2.2, 1  }

 gprint,basis,distance,angle
 gprint,orbital=104
 gexpec,DM

 hf
 orbital,2100.2

 {casscf;
  occ,28;
  closed,18;
  wf,50,,0;state,2;
  print,orbitals}
==============================

The other case can be reproduced by simply using the keyword basis=avdz instead
of the basis set block in the input above.

Could someone help us understand what is going on here? Should we get different
results, and if so, why? Is there another problem?

Best wishes,

Tanja
-- 
  =================================================================
   Tanja van Mourik
   Senior Lecturer in Chemistry
   School of Chemistry, University of St. Andrews
   North Haugh, St. Andrews, Fife KY16 9ST, Scotland (UK)

   email: tanja.vanmourik at st-andrews.ac.uk
   web:   http://chemistry.st-and.ac.uk/staffmember.php?id=tvm

   The University of St Andrews is a charity registered
   in Scotland: No SC013532
   =================================================================

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