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This is the default task of `relax` (`$optimize internal on`
does not need to be specified!) You need as input the data groups :
`$grad`
- cartesian coordinates and gradients as
provided and accumulated in subsequent optimization cycles by the
programs
`grad`, or `rdgrad` etc.
`$intdef`
- definitions of internal coordinates.
`$redundant`
- definitions of redundant coordinates.

Output will be the updated coordinates on `$coord` and the
updated force constant matrix on `$forceapprox`. If any
non-default force constant update option has been chosen, `relax`
increments its counting variables `<numgeo>`, `<numpul>`
within command keyword `$forceupdate`. If the approximate force
constant has been initialized (`$forceinit on`

) `relax` switches the initialization flag
to `$forceinit off`

. Refer also to
the general documentation of `TURBOMOLE`. It is recommended to check
correctness of your definition of internal coordinates:
- Calculate their values for your cartesian start coordinates
using the
`relax` program (see Section 5.3.11)
or within a `define` session.
- Have a look at the eigenvectors of the
**BmB**^{†}-matrix.
Set some ``?`

' behind keyword `$intdef`, if there are any
eigenvalues close to zero (
< 10^{-2} is to be considered bad
for small molecules, but there is no general rule) check those
internal coordinates for consistency which contribute to the
corresponding eigenvector(s)!

** Next:** Structure Optimization in Cartesian
** Up:** Program Relax
** Previous:** Definition of Internal Coordinates
** Contents**
** Index**
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