control as Input and Output File

define may be used to update an existing control file, which is helpful if only the basis set has been changed. In this case just keep all data, i.e. reply with on all questions, and only specify new start MOs. The more general usage is described now.

At the beginning of each define session, you will be asked to enter the name of the file to be created. As mentioned earlier, all TURBOMOLE programs require their input to be on a file named control, but it may be useful at this moment to choose another name for this file (e.g. if you have an old input file control and you do not want to overwrite it). Next you will be asked to enter the name of an old file which you want to use as input for this session. This prevents you from creating the new input from scratch if you want to make only minor changes to an old control file. It is possible to use the same file as input and output file during a define session (which means that it will only be modified). This may lead to difficulties, however, because define reads from the input file when entering each main menu and writes the corresponding data when leaving this menu. Therefore the input file may be in an ill-defined status for the next main menu (this will be the case, for example, if you add or change atoms in the first menu so that the basis set information is wrong in the second menu). define takes care of most--but not all--of these problems.

For these reasons, it is recommended to use a different filename for the input and the output file of the define session if you change the molecule to be investigated. In most cases involving only changes in the last three of the four main menus no problem should arise when using the same file as input and output.