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#44 Gaussian .fchk Checkpoint file

2.1
closed
nobody
Input (25)
5
2012-10-23
2006-02-13
Anonymous
No

In addition to other information, the Gaussian formatted checkpoint file
(.fchk) contains atomic numbers, atomic coordinates, etc.

This would be a useful input format to add.

Discussion

  • Maxim Fedorovsky

    Maxim Fedorovsky - 2007-01-29

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    Hello !
    I have already developed a parser (in Python) for Gaussian formatted checkpoint files, which can extract the following :

    1) geometry
    2) Hessian
    3) Raman / Raman optical activity data :
    a) derivatives of the polarizability tensor (alpha)
    b) derivatives of the optical rotation tensor (G')
    c) derivatives of the D-Q polarizability tensor (A)

    4) Infrared / vibrational circular dichroism data :
    a) Derivatives of the electric dipole moment (APT)
    b) Derivatives of the magnetic dipole moment (AAT)

    The hessian can be used to calculate the normal modes of a molecule with an arbitrary isotopic composition. MOLDEN format supports
    the saving of the normal modes. APTs are necessary to calculate the infrared spectrum.
    Since I have already done all these things, it would be not a big problem to reimplement it in C++ for OpenBabel :)

     

  • Geoff Hutchison

    Geoff Hutchison - 2007-03-12

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    Thanks to Maxim, I'm closing this. The current fchk reader (in the SVN trunk for 2.1) doesn't yet support matrix transformations required for Hessian / IR/Raman. But this can happen as soon as we migrate matrix inversion/diagonalization to Open Babel. (Hopefully for 2.2.)

    I'm marking this closed.
    -Geoff