## Firefly and PC GAMESS-related discussion club

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ifzmat is an array of fixed internals.
If you want to freeze an internal coordinate, you should add it into the ifzmat by the following way. First, you should write a type of internal
1 - bond
2 - angle
3 - dihedral
Then, you should specify numbers of all atoms that form this coordinate in the corresponding order. In your example ifzmat(1)=3,1,2,6,8 means that a dihedral of atoms with numbers 1,2,6,8 is frozen. ifzmat(1)=2,2,3,4, 3,1,2,6,8 means, that an angle of atoms 2,3,4 is frozen too.
If you make a surface scans, you should specify coordinates you wand to scan in ifzmat.

On Sat Dec 18 '10 3:33am, Gomathi wrote
---------------------------------------
>Hi,

>can anyone help me in explaining this following ifzmat.

>Thank you

>regards
>gomathi
>
>
>zmat dlc=1 auto=1 ifzmat(1)=3,1,2,6,8 scan=.t. DLCTOL=1D-7 \$end
> \$surf orig1=0 disp1=3 ndisp1=121 reuse=.t. \$end
>!
>! 2D scan
>! \$zmat dlc=1 auto=1 ifzmat(1)=2,2,3,4, 3,1,2,6,8 scan=.t. DLCTOL=1D-7 \$end
>! \$surf orig1=100 disp1=5 ndisp1=3 orig2=10 disp2=10 ndisp2=12 reuse=.t. \$end

> O           8.0   0.0374557837  -1.1027096878  -0.3376953819
> C           6.0  -0.7964523310   0.1095440073  -0.4758062859
> N           7.0   0.1154272554   1.2394362543  -0.2622262147
> C           6.0   1.2851496962   0.6560737192   0.3759656047
> O           8.0   1.1964117525  -0.7958132340   0.1745293777
> C           6.0  -1.9330312967   0.0214472911   0.5314082852
> H           1.0  -1.5375980169  -0.0389777264   1.5730971108
> H           1.0  -2.5258618719  -0.9004185610   0.3200348483
> H           1.0  -2.5919598392   0.9167531937   0.4409660129
> H           1.0  -1.1990582309   0.0737050240  -1.5269253078
> H           1.0   0.3526816463   1.6713979564  -1.1350298150
> H           1.0   1.2501648737   0.8326689594   1.4840207961
> H           1.0   2.2629141988   0.9831942031  -0.0617411589

Sat Dec 18 '10 12:37pm