qmd problem


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hello,

I got a restart file problem about qmd module.

For ch3cl+F reaction, I gave the F atom an initio velocity along with -z axe and a impact parameter set in y axe. Mass center of ch3cl set in (0,0,0).

Here, the problem is no matter how big the impac parameter I defined, the reaction trajectory always act head-to-head pathway, even at a very large impact parameter in
where the reaction shouldn't happen.

In other words, the intio velocity didn't along with the -z axe. Restart file is shown below:

  6

    0        0

Coordinates
-1.824244144 -7.48317E-10 3.203477886
0.912122073 -1.579841771 3.203477886
0.912122072 1.579841772 3.203477886
0 0 2.26913006
0 0 -1.041995138
0 8 15
Velocities
0 0 0
0 0 0
0 0 0
0 0 0
0 0 0
0 0 -0.001460

I would appreciate that if you can give me a hint.

Li

Forum Regular
My guess is that your problem stems from the code removing center-of-mass translations and rotations. Unfortunately, at this time there is nothing you can add to your input file to change this behavior as the code is set up to always remove COM translations and rotations before starting. However, it is very easy to modify the source code to bypass this step. In $NWCHEM_TOP/src/qmd/qmd_driver.F, simply comment out any calls to the subroutine qmd_fix_momentum and recompile. This will stop the code from removing COM translations and rotations.

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