Preparing your input file with DEFINE

define is the general interactive input generator of TURBOMOLE. During a session with define, you will create the control file which controls the actions of all other TURBOMOLE programs. During your define session you will be guided through four main menus:

1. The geometry main menu: This first menu allows you to build your molecule, define internal coordinates for geometry optimizations, determine the point group symmetry of the molecule, adjust internal coordinates to the desired values and related operations. Beyond this one can perform a geometry optimization at a force field level to preoptimize the geometry and calculate a Cartesian analytical Hessian. After leaving this menu, your molecule to be calculated should be fully specified.
2. The atomic attributes menu: Here you will have to assign basis sets and/or effective core potentials to all atoms. The SV(P) basis is assigned automatically as default, as well as ECPs (small core) beyond Kr.
3. The occupation numbers and start vectors menu: In this menu you should choose eht to start from Extended Hückel MO vectors. Then you have to define the number of occupied orbitals in each irreducible representation.
4. The general menu: The last menu manages a lot of control parameters for all TURBOMOLE programs.

Most of the menu commands are self-explanatory and will only be discussed briefly. Typing * (or q) terminates the current menu, writes data to control and leads to the next while typing & goes back to the previous menu.