CFOUR makes use of a small number of formatted and unformatted files which contain various pieces of information relating to the calculation. For the most part, these files are direct access files which have an implicit logical record structure. This means that the programs which read from and/or write to these files treat the information in chunks (logical records) which do not correspond directly to the physical structure of the file on the disk drive. Translation between the logical and physical structure of the files is handled by specialized I/O routines (GETLST, PUTLST, GETREC and PUTREC). The following section lists all of the permanent files used by CFOUR.
ZMAT
is the primary user interface to CFOUR, and it must exist in the run directory.
GENBAS
The GENBAS file contains the basis set definitions that the program can use.
ECPDATA
This file contains the data for effective core potentials.
GUESS
The GUESS file is used to control the “placement” of electrons and to “manipulate” orbitals when the SCF initial guess is read from an external file named OLDMOS.
NEWMOS, OLDMOS
These files contain the MOs (in the symmetry-adapted AO basis) of the SCF wavefunction. NEWMOS is created by the SCF program after the last iteration, and the user can copy this file to OLDMOS to initialize the MOs of a later calculation on the same molecule and basis set.
FCMINT, FCM, FCMSCR, and FCMFINAL
FCMINT contains the full internal coordinate force constant matrix. The other files, FCM, FCMSCR, and FCMFINAL, correspond to the symmetrized, mass-weighted, and analytical force constant matrices, respectively.
ISOMASS
Vibrational frequencies can be calculated with standard atomic masses or user-supplied masses — usually of isotopes. If a file named ISOMASS is found, then the vibrational frequency logic in joda replaces the atomic masses with those found in the file. The content is free format ASCII, and the order of the masses must match the non-dummy centers in ZMAT.
JOBARC, JAINDX
The JOBARC file stores records (named arrays) for the CFOUR program system. The accompanying file JAINDX stores metadata about the records.
OPTARC
This file contains information about the progress of optimizations and is a historical carry-over from the old days. Eventually, this file will probably be phased out with its information being moved over to JOBARC. This file has a sequential structure with relatively large records, and the number of records always equals the number of optimization cycles plus one. OPTARC records are written by subroutine ARCHIVE in joda.f and are read by subroutine RETRIEVE in the same program.
JODADONE
This file contains a single empty sequential record and is written by xjoda when an optimization has terminated. Its presence is used by CFOUR to test for the convergence of an optimization. It is written by subroutine EFOL of joda.f.
FCMINT
This file contains the full square internal coordinate force constant matrix and can be used to initialize the Hessian in geometry optimizations.
MOINTS, GAMLAM, MOABCD, DERINT, DERGAM
These five files are actually treated as a single file by the program system, and contain the integral and amplitude lists used by the post-SCF program modules. As such, these files can become quite large and will always take up most of the disk space in actual calculations. The only difference between these files is the lists which are stored on them. MOINTS contains list numbers 1-100; GAMLAM contains lists 101-200; MOABCD contains lists 201-300; DERINT contains lists 301-400; and DERGAM contains lists 401-500. These files are composed of direct access records with an imposed logical record structure, and all I/O is supervised by the GETLST and PUTLST subroutines and their dependent routines FETCH and DUMP.
MOL, IIII, IIJJ, IJIJ, IJKL
The MOL file is created by xjoda and stores the molecular system and basis set information used by xvmol. The IIII, IIJJ, IJIJ, and IJKL files store the two-electron integrals in the AO basis. The one-electron integrals are also stored in IIII.
DIPOL, DIPDER, POLAR, POLDER DIPOL and POLAR
contain the dipole moments and polarizabilities, respectively, and DIPDER and POLDER contain their derivatives.
GRD
This file contains the gradients.
HF2, HF2AA, HF2AB, HF2BB
These files are created by xvtran and store partially-transformed two-electron integrals for use in xintprc. Usually they are deleted by xintprc unless a particular post-SCF option requires them (such as ABCDTYPE=MULTIPASS).
VPOUT
This file contains the first-order property integrals.
CFOUR is partially supported by the U.S. National Science Foundation.