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Keywords for Module UFF
One has to specify only the Cartesian coordinates (data group
$coord) to start a uff run.
The program uff requires the data groups $uff,
$ufftopology, $uffgradient and $uffhessian. If
these keywords do not exist in the control file the program will
generate these data groups.
The data group $uff contains the parameters described below. The
default valuesin the control fileare:
1 1 0 ! maxcycle,modus,nqeq
111111 ! iterm
0.10D07 0.10D04 ! econv,gconv
0.00 1.10 ! qtot,dfac
0.10D+03 0.10D04 0.30 ! epssteep,epssearch,dqmax
25 0.10 0.00 ! mxls,dhls,ahls
1.00 0.00 0.00 ! alpha,beta,gamma
F F F ! transform,lnumhess,lmd
The explanation of the variables are as follows:
 maxcycle

number of max. optimization cycles (maxcycle=1:
singlepoint calculation).
 modus

can have the values +1 or 1. If modus = 1
only the topology will be calculated.
 nqeq
 each nqeq cycle the partial charges will be
calculated. If
nqeq = 0
, then the partial charges are calculated only in the first
cycle, if the file
ufftopology does not exist.
 iterm

switch for the different types of force field terms:
 100000
 bond terms will be calculated.
 010000
 angle terms will be calculated.
 001000
 torsion terms will be calculated.
 000100
 inversion terms will be calculated.
 000010
 non bonded van der Waals terms will be
calculated.
 000001
 non bonded electrostatic terms will be
calculated.
 econv, gconv

convergence criteria for energy and gradient.
 qtot
 total charge of the molecule.
 dfac
 distance parameter to calculate the topology. If the
distance between the
atoms I and J is less than the sum of the covalent radii of the the atoms
multiplied with
dfac, then there is a bond between I and J.
 epssteep

if the norm of the gradient is greater than epssteep, a
deepestdescentstep will be done.
 epssearch

if the norm of the gradient is smaller than epssearch, no
linesearch step will be done after the Newton step.
 dqmax

max. displacement in a.u. for a coordinate in a relax step.
 mxls, dhls, ahls

parameters of linesearch:
 ahls
 start value
 dhls
 increment
 mxls
 number of energy calculations
 alpha, beta, gamma

modification parameter for the eigenvalues of the Hessian (see
below):
f (x) = x*(alpha + beta*exp( gamma*x)).
 transform

a switch for the transformation in the principal axis system.
 lnumhess

a switch for the numerical Hessian.
 lmd
 a switch for a MD calculation.
Subsections
Next: Input Data Blocks Needed
Up: Format of Keywords and
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TURBOMOLE