CCL: Estimated job time in Gaussian

["Rzepa, Henry S" <h.rzepa^-^imperial.ac.uk>]

 Sent to CCL by: "Rzepa, Henry S" [h.rzepa*imperial.ac.uk]
 In terms of estimating time, geometry optimisation is in itself a black art.
 Sometimes the accuracy limits, either set by default or by the user, can greatly
 influence the time taken, as can the coordinate system chosen. It is always
 useful to "tail" the job output and take a look at the number of
 geometry cycles and whether the preset convergence criteria are close to being
 met, or in fact oscillating (which can happen).
 Convergence of other algorithms (eg 2nd  derivatives,  VCD etc etc) can depend
 greatly on integral accuracy  (ie acc2e=14  often solves that problem) and other
 presets.  So there is really no general answer to estimating job times.
 Henry
 > On 3 Jan 2022, at 10:28, Detlev Conrad Mielczarek detlevcm~!~googlemail.com
 <owner-chemistry++ccl.net> wrote:
 >
 >
 > Sent to CCL by: Detlev Conrad Mielczarek [detlevcm_._googlemail.com]
 > Estimating compute times is its own area of research and typically very
 hard to do - not just in ab initio quantum chemistry but also in other fields,
 say CFD.
 >