[molpro-user] Query Regarding MATROP in MOLPRO

Tatiana Korona tania at tiger.chem.uw.edu.pl
Fri Oct 16 10:34:55 BST 2015

Dear Sachin,

If you analyse e.g. the MP2 density matrix, then it can have a couple of 
negative eigenvalues due to either a multiconfigurational character of the 
molecule under study, or because of HF instabilities, see

Gordon et al., The Journal of Chemical Physics 110, 4199 (1999); doi: 

Westin Kurlancheek & Martin Head-Gordon (2009) Molecular Physics, 107:8-12, 

It is however strange that a method outside molpro and matrop give different 
results, but without more data it is impossible to say why. I would vote that 
matrop is correct:-)

Best wishes,


  On Thu, 15 Oct 2015, Sachin D Yeole wrote:

> Dear MOLPRO Team,
> I am using matrop command in MOLPRO for
> saving and diagonalizing one electron hamiltonian
> and density matrix.
> My query is the eigen values for density matrix contain few negative numbers
> is it normal? I expect all of them to be positive.
> and the eigenvalues for hamiltonian and density matrix are different when I try
> jacobi method outside the molpro. (or any suggestion for using other better method)
> What is the format for printing the matrix elements in a file by "write" command
> (I assumed as ((MIJ, loop over rows) loop over columns)
> I would appreciate if someone could provide the answers of these queries.
> thanks
> Sachin...
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Dr. Tatiana Korona http://tiger.chem.uw.edu.pl/staff/tania/index.html
Quantum Chemistry Laboratory, University of Warsaw, Pasteura 1, PL-02-093 Warsaw, POLAND

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