next up previous contents index
Next: Look at Results Up: Program Relax Previous: The m-Matrix   Contents   Index


Initialization of Force Constant Matrices

The most simple initial hessian is a unit matrix. However, better choices are preferable. For structure optimizations using internal coordinates you may use structural information to set up a diagonal force constant matrix with elements chosen in accord to the softness or stiffness of the individual modes. For detailed information refer to ref. [36]. For optimization of basis set parameters less information is available. When neither data block $forceapprox is available nor $forceinit on is set, the force constant matrix will be initialized as a unit matrix. Specifying the force constant initialization key $forceinit on diag=... will lead to:
diag=real
Initialization with real as diagonal elements.
diag=default
Initial force constant diagonals will be assigned the following default values:
internal coordinates : stretches 0.50
angles 0.20
scaling factors : s,p 1.50
d 3.00
exponents : uncontracted 0.15
contracted 10.00
contraction coefficients :100.00
global scaling factor :15.00
cartesian force constants :0.50
diag=individual
Initial force constant diagonals will be taken from
$intdef fdiag=... or
$global fdiag=...
Similar initialization modes are NOT supported for geometry optimization in cartesian space and for the optimization of basis set parameters!
carthess
Data group $hessian (projected) is used.


next up previous contents index
Next: Look at Results Up: Program Relax Previous: The m-Matrix   Contents   Index
TURBOMOLE M