Optimization to minima and transition structures using STATPT

Structure optimizations can be carried out by the program statpt. For minimizations no additional keywords are required. The default values are assumed, which work in most of the cases. Structure optimization is performed in internal coordinates if they have been set. Otherwise, Cartesian coordinates are used. One can switch the optimization in internal coordinates on or off, respectively in internal redundant or cartesian coordinates. For transition structure optimizations the index of transition vector has to be set to an integer value > 0 (0 means structure minimization). The value of the index specifies transition vector to follow during the saddle point search. Note, that Hessian eigenpairs are stored in ascending order of the eigenvalues, i.e. the eigenpair with the smallest eigenvector has the index 1.

The command stp gives:

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 CONVERGENCE CRITERIA:

 thre  1.000000E-06     thre : threshold for ENERGY CHANGE
 thrd  1.000000E-03     thrd : threshold for MAX. DISPL. ELEMENT
 thrg  1.000000E-03     thrg : threshold for MAX. GRAD. ELEMENT
 rmsd  5.000000E-04     rmsd : threshold for RMS OF DISPL.
 rmsg  5.000000E-04     rmsg : threshold for RMS OF GRAD.

 defl : set default values.

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 OPTIMIZATION refers to

 int   off         int: INTERNAL coordinates
 rdn   off         rdn: REDUNDANT INTERNAL coordinates
 crt   on          crt: CARTESIAN coordinates
 NOTE : options int and crt exclude each other

 ENTER STATPT-OPTIONS TO BE MODIFIED

 itvc    0              itvc : change INDEX OF TRANSITION VECTOR
 updte   bfgs           updte: change method of HESSIAN UPDATE
 hsfrq   0              hsfrq: frequency of HESSIAN CALCULATION
 kptm    0              kptm : FREEZING transition vector INDEX
 hdiag 5.000000E-01     hdiag: change DIAGONAL HESSIAN ELEMENTS
 rmax  3.000000E-01     rmax : change MAX. TRUST RADIUS
 rmin  1.000000E-04     rmin : change MIN. TRUST RADIUS
 trad  3.000000E-01     trad : change TRUST RADIUS
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 Just <ENTER>, q or '*' terminate this menu.