Ceilidh ... Re^2: divergence gemetrical optimization of tetracene

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Re^2: divergence gemetrical optimization of tetracene

IFREEZE should only be used when your data group is in the Z-matrix format: in your input file, you are instructing the program to freeze the coordinates 10,15,16 and 20 (i.e the x coordinate of the 4th atom, z-coord at the 5th, x-coord on the 6th, and y-coord on the 7th). In order to freeze bonds with xyz-coordinates, you should use ifzmat() and perform the geometry optimization using delocalized coordinates, invoked with $zmat dlc=1 auto=1 $end (which gives much faster convergence anyway). The only drawback in using dlc is that you should also explicitly define every bond which is longer than usual with $zmat nonvdw(), otherwise the program will not recognize them. In your input, that means manually adding every C-H bond, as well as the long "bonds" defining the distances you want to freeze.
I attach a corrected input file
Pedro

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[ bent_antracene_input.txt ] Corrected input for bent antracene MP2 optimization

Wed Feb 4 '09 1:57pm

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