12 Interfacing a new module in MOLPRO

The mechanism for linking a completely new piece of code into MOLPRO is as follows. In response to the USER data command, the command subroutine leit (src/util/driver.f) simply calls the subroutine user without arguments. The default stub in src/util/user.f simply terminates. Thus the procedure is to create a file user.f in a MOLPRO develop directory, containing subroutine user which then should run the code which is being introduced.