Incorrect results in calculating H2 molecule

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Norio Saito
Posts: 4
Joined: Wed Nov 06, 2013 2:50 pm

Incorrect results in calculating H2 molecule

Post by Norio Saito » Sun Nov 17, 2013 4:05 am

Hi,

I'm trying to calculate H2 molecule to see the tutorial page.
However, the calculation results are different from those of the tutorial in spite of using the "file" file and "input" file copied from the examples.
(file names in the "file" file are correctly edited.)

While I run the code and it is completed without any errors, the results (total energy=-2.329Ha, optimal interatomic distance=0.7880Bohr) apparently differ from the tutorial (total energy=-1.1058Ha, optimal interatomic distance=1.522Bohr). Here is a part of my output,

Code: Select all

           etotal     -2.3286013998E+00
           xcart      -3.9398327575E-01  0.0000000000E+00  0.0000000000E+00
                       3.9398327575E-01  0.0000000000E+00  0.0000000000E+00


I'm using ABINIT version 7.4.3 built with gcc4.8, which is slightly different from the environment of the tutorial.
But, I don't know whether it is related with this problem.
Please tell me how to manage this problem.

Norio Saito.
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ljludwig
Posts: 77
Joined: Fri Jun 08, 2012 5:19 am

Re: Incorrect results in calculating H2 molecule

Post by ljludwig » Thu Dec 05, 2013 12:31 am

I really don't think there is anything to do with the Abinit version or compiler version. Could you show your input file?

Ah, I know what's your problem. The interatomic distance is 0.7880Bohr? Which is WRONG. I think it is likely to be doubled, or you used a wrong unit system.

See here: http://www.abinit.org/documentation/hel ... base1.html
It says "The forces vanish also between 1.5 Bohr and 1.55 Bohr".

In your case it is halved.

Please mark the question as solved if you think it is. Thanks!
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