Greetings,
In these days i'm trying to optimize the geometry of a polynuclear complex using G09 with B3LYP and 6-31++G(d,p) basis set (commands bellow). But at the end of 7th day of computation, i had a bad message:
(...)
EnCoef did 3 forward-backward iterations
Restarting incremental Fock formation.
Restarting incremental Fock formation.
Restarting incremental Fock formation.
Restarting incremental Fock formation.
Restarting incremental Fock formation.
Restarting incremental Fock formation.
>>>>>>>>>> Convergence criterion not met.
SCF Done: E(RB3LYP) = -4724.56420437 A.U. after 129 cycles
NFock=128 Conv=0.31D-07 -V/T= 2.0040
Convergence failure -- run terminated.
Error termination via Lnk1e in C:\G09W\l502.exe at Sun Mar 29 18:34:42 2020.
Job cpu time: 7 days 7 hours 17 minutes 52.0 seconds.
File lengths (MBytes): RWF= 369 Int= 0 D2E= 0 Chk= 46 Scr= 1
It took so long to failure. Can i continue this job using my checkpoint file? Is it worth continuing or should i start a new job?
command (first line)
#n B3LYP/6-31++G(d,p) Opt Pop=(Reg, Orbitals=9) Formcheck
Lucas Almir Cavalcante Minho try to reduce the convergence criteria. add MaxCycle=700 or more in the keyword section. Probably it may give you the result.
Hey Lucas Almir, from the message which you got as a failure it can even be a problem with the memory. It doesn't mean that you have not enough space, but sometimes you need to specify the memory in the input file. Another possible reason can be your options for the convergence: you might need to change them. Here is how these options look like for G16: https://gaussian.com/scf/
The third issue can be your starting geometry. In that case you just need to make another geometry for the same molecule.
The default maximum number of SCF cycles is 64. As suggested by @Aadhityan Arivazhagan, increasing the number of SCF cycles may solve the problem. Using SCF keyword with MaxCycle option, for example SCF=(MaxCycle=512), may solve the problem. Alternatively you can use SCF=QC. For QC option, default maximum number of SCF cycles is 512. I hope it helps.
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