Author Topic: electric field  (Read 6589 times)

sdTurb

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electric field
« on: August 14, 2008, 07:33:15 PM »
Im applying an electric field across a molecule and measuring the electric potential using the potential command in the prop menu . I just have a few questions about the output?

What are the boundary conditions in turbomole? Does the electrostatic  potential given by moloch include the external field ? Does it include the poission equation?

uwe

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Re: electric field
« Reply #1 on: September 11, 2008, 04:28:41 PM »
Hello,

as far as I understand, the question refers to the module moloch. This program plots the electrostatic potential arising from nuclei and electrons. In case of a (constant) external electric field the additional (linear) potential is NOT added.

Please note, that the module moloch will no longer exist in the next version, but already in 5.10 nearly all functionalities of moloch are available directly from the programs calculating the wave functions (dscf, ridft, mpgrad, rimp2, escf). For setting of keywords see manual. If the respective wave function (or density matrix) does already exist, these programs may be called with the suffix "-proper", so that only the calculation of properties is carried out, see also manual. The following statements concerning the calculation of electrostatic potential in presence of external electric fields refer to this mode:

  • The linear term from the field IS added (and also that of point charges in case of existence).
  • If one is not interested in these terms, it is probably the best to delete the respective keywords ($fldopt, $electrostatic field, $point_charges) after convergence of the SCF procedure and to rerun the respective program with suffix "-proper".
  • If one is interested in the electrostatic potential from the electrons only, one may add "eonly", e.g.: "$pointval pot eonly".

One may easily check this by calculating the electrostatic potential at point(s) far away from a molecule.

Regards,

Uwe (on behalf of Florian)