Gaussian 03 Online Manual
This output specification keyword allows the user to "punch"-in more modern parlance, send to a separate output file-useful information at various points in the calculation. The output is disposed of in whatever manner is usual for Fortran alternate-unit output under the appropriate operating system (for example, unit 7 is sent to the file fort.7 under UNIX.) Options are used to specify what information should be output. All of these options can be combined, except that only one of MO and NaturalOrbitals can be requested. Note, however, that they are distinct and non-interacting. For example, Punch(MO, Gamess) sends both the molecular orbital and Gamess input information to the file; it does not format the MO information in Gamess input format.