Fa(1,1) Fa(2,1) Fa(2,2) Fa(3,1) Fa(3,2) Fa(3,3) ... Fa(nbasis,nbasis)
Fb(1,1) Fb(2,1) Fb(2,2) Fb(3,1) Fb(3,2) Fb(3,3) ... Fb(nbasis,nbasis)

An example:

   -0.4757896E+00 -0.1304262E+01 -0.2454798E+02 -0.9542753E+00 -0.6323017E+01
   -0.2779498E+01  0.0000000E+00  0.0000000E+00  0.0000000E+00 -0.3592725E+00
    0.0000000E+00  0.0000000E+00  0.0000000E+00  0.0000000E+00 -0.4596172E+00
    0.3750725E+00  0.7017446E-02  0.7801171E-01  0.0000000E+00  0.0000000E+00
   -0.4480536E+00
   -0.3050038E+00 -0.1298838E+01 -0.2451823E+02 -0.9135569E+00 -0.6297229E+01
   -0.2653196E+01  0.0000000E+00  0.0000000E+00  0.0000000E+00 -0.3098520E+00
    0.0000000E+00  0.0000000E+00  0.0000000E+00  0.0000000E+00 -0.1255388E+00
    0.3550253E+00  0.4693878E-02  0.5264584E-01  0.0000000E+00  0.0000000E+00
   -0.3481476E+00

You can use NPRINT=5 in GAMESS-US input file, Fock matrix will be printed at each SCF iteration, you should take the "TOTAL FOCK OPERATOR" printed last time in the output file.

Thank you Tian! I have obtained two Fock matrices "ALPHA TOTAL FOCK MATRIX" and  "BETA TOTAL FOCK MATRIX".
Should I put it in one file as two lines - "Fa(1,1) Fa(2,1) Fa(2,2) Fa(3,1) Fa(3,2) Fa(3,3) ... Fa(nbasis,nbasis)" and "Fb(1,1) Fb(2,1) Fb(2,2) Fb(3,1) Fb(3,2) Fb(3,3) ... Fb(nbasis,nbasis)" or use two separate files?

Dear Tian,

Thank you for a quick response!  Please, may I ask you to give me more detailed instructions how to obtain DFT Fock matrix from Gamess US/Firefly output.  I try to perform unrestricted B3LYP calculations with the highest level of NPRINT but cannot find any specific section with the matrix values in *.out(*.gms) or *.dat(PUNCH) files.

Kind regards,
Alexey

You can use NPRINT=5 in GAMESS-US input file, Fock matrix will be printed at each SCF iteration, you should take the "TOTAL FOCK OPERATOR" printed last time in the output file.

Thank you for a quick response!  Please, may I ask you to give me more detailed instructions how to obtain DFT Fock matrix from Gamess US/Firefly output.  I try to perform unrestricted B3LYP calculations with the highest level of NPRINT but cannot find any specific section with the matrix values in *.out(*.gms) or *.dat(PUNCH) files.

Kind regards,
Alexey

Full MO biorthogonalization is also possible for GAMESS-US user.

You need to perform UHF or UKS calculation by GAMESS-US/Firefly and then change the suffix of output file to .gms, then this file can be used as input file of Multiwfn to perform biorthogonalization. In order to obtain energies of biorthogonalized orbitals, as mentioned in Section 3.100.12 of Multiwfn manual, you need to ask GAMESS-US to print Fock or KS matrix, then manually write the matrix elements into a file in lower-triangular form, namely in this sequence: F(1,1) F(2,1) F(2,2) F(3,1) F(3,2) F(3,3) ... F(nbasis,nbasis). You may need to write a small code to realize the format conversion.

Best regards,

Tian

Please, may I ask you to help me with a problem. I'm working with Gamess-US and Firefly. Is it any way to perform full  MO biorthogalization (biorthogalization, new energies calculation and their reordering) using Mutiwfn  and these programs only?  I have found your example in the manual but unfortunately Gaussian program is needed for do this.

Best regards,
Alexey