Linear Transit

In a continued Linear Transit (LT) calculation the continuation run proceeds from where the previous run stopped. The total number of points by which the transit is scanned, the current point (its index and the Cartesian coordinates), the accumulated results of completed points on the transit etc. are copied from the restart file. If the restart file contains a section LT, then all relevant data must be present on it and correct (i.e. matching those of the current run: same number of LT parameters, and of course the same molecule.

LT%nr of points

The number of points by which the LT is scanned; this is identical to the Fortran variable ltimax in the code. The value on the restart file applies in the calculations and overwrites any input/default value (see the subkey lineartransit of the geometry block)

lt%current point

Index of the current LT scan point. This is where the program will continue. In a non-restart LT run, this index initializes at 1.

LT%Energies

An array with energy values, one for each LT point. When the LT run is completed, this array allows you to map out the energy along the LT path. The values for the completed LT points are stored on the restart file. This size of the array on the restart file must (at least) be the total number of points on the complete path.

LT%Parameters

Initial and final values for the LT parameters, which describe roughly the path (all other coordinates may be optimized at each point, depending on other input keys). The values from the restart file overwrite input values. The input values should be supplied, however, as if it were a non-restart run.

LT%atmcrd

zmat if a z-matrix structure is available for the molecule, cart otherwise. This is used to control printing of results. It does not define the type of optimization variables: see the next item.

LT%geocrd

zmat or cart: the type of optimization variables. This defines in which type of coordinates the LT parameters are defined and any optimization of other coordinates takes place.

LT%xyz

Cartesian coordinates for all LT points: 3*atoms*ltpoints. The size of the array must conform to this. Only the values of the completed LT points and those of the current point are relevant. Those of the current LT point are used as initial coordinates to start the current run.

LT%zmatrix

Same for the Z-matrix coordinates. They should match the Cartesian coordinates for the completed LT points (this is not checked). Those for the current LT point will be recomputed from the current Cartesian coordinates.