CCL:G: Magnitude of static field used for calculation of polarizability

 Sent to CCL by: Susi Lehtola [susi.lehtola^^]
 On 04/25/2018 04:22 PM, Suresh Kumar Venkata Neelamraju
 nvs.kumar^^ wrote:
 Sent to CCL by: "Suresh Kumar Venkata Neelamraju"
 [] Dear members of CCL,
 Can anyone please inform the magnitude of static field used by
 Gaussian09 for calculation of static polarizability.
One does not need a field to calculate static polarizability. It can be solved at zero field as the second derivative of the molecular energy using a response formalism. This appears to be the approach used in Gaussian.
If you do not have a program that supports this approach, you can always estimate the static polarizability by finite differences. (A static field is very easy to implement, as it only requires dipole integrals.) You can then run calculations at several values of the field (as well as all field directions), and estimate the polarizability using e.g. a three- or five-point stencil.
 Mr. Susi Lehtola, PhD             Junior Fellow, Adjunct Professor
 susi.lehtola-$   University of Helsinki  Finland
 Susi Lehtola, dosentti, FT        tutkijatohtori
 susi.lehtola-$   Helsingin yliopisto