[gmx-developers] g_dipole: dipole moment autocorrelation function

[Nilesh Dhumal]

THanks for your reply.

I calculated the dipole autocorrelation function with normalization.

I was expecting some exponential type plot. Its not at all soomth and not
converges to zero.

I am trying to calculate the vibrational spectra by Fourier transform of
diople moment autocorrelation function.

Thanks Nilesh


On Tue, March 22, 2011 4:51 pm, David van der Spoel wrote:
> On 2011-03-22 21.39, Nilesh Dhumal wrote:
>
>> Hello,
>>
>>
>> I wrote to gmx-users many times but never got reply.  I am posting this
>>  message to developer.
>>
>>
>> I am trying to calculate the non normalized dipole moment
>> autocorrelation function for water. I am using flexible spc water model
>> (define=-DFLEX_SPC). I am using gromacs 4.0.7 version.
>>
>>
>> I run the simulation for 4 ns.  I run the following command to
>> calculate the dipole moment autocorrelation function
>>
>> g_dipoles -f water.trr -s water.tpr -nonormalize -corr total -c
>>
>> I am geting the value really high starts from +5000 to -100
>> (dipcorr.xvg).
>>
>>
>> Is there anything wrong and function is not geting converge to zero.
>>
>>
>> Thanks
>>
>>
>> Nilesh
>>
>>
>>
>>
> You turned off the normalization. It does fall off to -100/5000 = -0.02
> if you would normalize.
>
>
> --
> David van der Spoel, Ph.D., Professor of Biology
> Dept. of Cell & Molec. Biol., Uppsala University.
> Box 596, 75124 Uppsala, Sweden. Phone:	+46184714205.
> spoel at xray.bmc.uu.se    http://folding.bmc.uu.se --
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