Molcas Forum

Sarah

Member

Registered: 2016-08-01

Posts: 40

Hessian extraction

Dear all,

I want to extract hessian from Molcas output.

Here is my input for a single water molecule:

GATEWAY
 coord
 3
Title Card Required
 O      0.13004   0.00000   0.00000
 H      0.69358   0.00000   0.75278
 H      0.69358   0.00000  -0.75278
Basis=6-31g*
group=C1
>>>  Export  MOLCAS_MAXITER=100
>>>  Do  while

  &SEWARD
  &SCF;  Title="H2O  minimum  optimization"
  &SLAPAF

>>>  EndDo

&MCKINLEY
Perturbation
Hessian
ShowHessian

in the output I get the following:

  Hessian in Irrep a
  ------------------
  mat. size =    9x   9

   -3.00319924
    0.00000000 -4.66639088
   -0.00000000 -0.00000000 -1.20648814
    1.50159962 -0.00000000 -1.21260882 -1.46985456
   -0.00000000  2.33319544 -0.00000000  0.00000000 -2.31006926
   -1.24279690 -0.00000000  0.60324407  1.22770286  0.00000000 -0.63707302
    1.50159962 -0.00000000  1.21260882 -0.03174506  0.00000000  0.01509404 -1.46985456
   -0.00000000  2.33319544  0.00000000  0.00000000 -0.02312618  0.00000000  0.00000000 -2.31006926
    1.24279690  0.00000000  0.60324407 -0.01509404 -0.00000000  0.03382895 -1.22770286 -0.00000000 -0.63707302
 *************************
 *                       *
 *Complete static Hessian*
 *                       *
 *************************

  Hessian in Irrep a
  ------------------
  mat. size =    9x   9

    0.38573067
    0.00000000 -0.03063072
    0.00000000  0.00000000  0.51302956
   -0.19286534 -0.00000000 -0.14227720  0.16400218
   -0.00000000  0.01531536 -0.00000000  0.00000000 -0.03084826
   -0.22331404 -0.00000000 -0.25651478  0.18279562  0.00000000  0.27660583
   -0.19286534 -0.00000000  0.14227720  0.02886316  0.00000000  0.04051842  0.16400218
   -0.00000000  0.01531536  0.00000000  0.00000000  0.01553290  0.00000000  0.00000000 -0.03084826
    0.22331404  0.00000000 -0.25651478 -0.04051842  0.00000000 -0.02009106 -0.18279562 -0.00000000  0.27660583

1. Is "Complete static Hessian"  what we need to extract?
2. should we put zero in the place of above diagonal matrix elements?
3. what about large molecules, for larger molecules this part is very messy; is there any general way to extract hessian?

Thank you in advance