A `Quick and Dirty' Tutorial

A straightforward way to perform a `TURBOMOLE` calculation
from scratch is as follows:

- generate your atomic coordinates by any tool or program you are familiar with,
- save it as an
`.xyz`file which is a standard output format of all programs, or use a conversion tool like`babel`, - use the
`TURBOMOLE`script`x2t`to convert your`.xyz`file to the`TURBOMOLE``coord`file:

`x2t xyzinputfile > coord`

- call
`define`; after specifying the title, you get the coord menu--

just enter`a coord`

to read in the coordinates.

Use`desy`to let`define`determine the point group automatically.

If you want to do geometry optimizations, we recommend to use generalized internal coordinates;`ired`generates them automatically. - you may then go through the menus without doing anything: just
press
`<Enter>`

,`*`

or`q`

--whatever ends the menu, or by confirming the proposed decision of`define`again by just pressing`<Enter>`

.

This way you get the necessary specifications for a (SCF-based) run with SV(P) as the default basis set which is roughly 6-31G*. - for more accurate SCF or DFT calculations choose larger basis
sets, e.g. TZVP by entering
`b all def-TZVP`

or`b all def2-TZVP`

in the basis set menu. - ECPs which include (scalar) relativistic corrections are automatically used beyond Kr.
- an initial guess for MOs and occupation numbers is provided by
`eht`

- for DFT you have to enter
`dft`

in the last menu and then enter`on`

- for efficient DFT calculations you best choose the RI
approximation by entering
`ri`

and providing roughly 3/4 of the memory (with`m`*number*;*number*in MB) your computer has available. (Auxiliary basis sets are provided automatically) In the printout of an`ridft`run you can check how much is really needed; a`top`

statement will tell you if you overplayed your cards. - B-P86 is the default functional. It has a good and stable performance throughout the periodic system.
- for an HF or DFT run without RI, you simply enter:

`[nohup] dscf > dscf.out &`

or, for a RI-DFT run:

`[nohup] ridft > ridft.out &`

- for a gradient run, you simply enter:

`[nohup] grad > grad.out &`

or

`[nohup] rdgrad > rdgrad.out &`

- for a geometry optimization simply call
`jobex`:

for a standard SCF input:

`[nohup] jobex &`

for a standard RI-DFT input:

`[nohup] jobex -ri &`

- many features, such as NMR chemical shifts on SCF and DFT level,
do not require further modifications of the input, just call e.g.
`mpshift`after the appropriate energy calculation (mpshift runs with SCF or DFT using a hybrid-functional need a file size of the semi-direct file`twoint`that is non-zero). - other features, such as post-SCF methods need further action on the input,
using either the last menu of define where one can activate all settings
needed for DFT, TDDFT, MP2, CC2, etc. calculations (this is the recommended way),
or tools like
`Mp2prep`or`Rimp2prep`. Please refer to the following pages of this documentation.

- Single Point Calculations: Running TURBOMOLE Modules
- Energy and Gradient Calculations
- Calculation of Molecular Properties
- Modules and Data Flow