[gmx-users] g_dipoles output

[Martin Höfling]

Hi Folks, 

I struggle with the output of g_dipoles, just to make sure that I understood 
it right:

I select a subpart of my simulation and get the following output:

> Average volume over run is 216
>
> Dipole moment (Debye)
> ---------------------
> Average  =   0.4463  Std. Dev. =   0.5010  Error =   0.0003

Is this the dipole moment of my group normalized to the volume? I especially 
do not understand the difference between this value and the following ones.

> The following averages for the complete trajectory have been calculated:
>
>  Total < M_x > = -2.20102 Debye
>  Total < M_y > = -1.65231 Debye
>  Total < M_z > = -2.24414 Debye

OK these are the component average values over time from dipole moment of my 
group.

>  Total < M_x^2 > = 1200.66 Debye^2
>  Total < M_y^2 > = 1200.07 Debye^2
>  Total < M_z^2 > = 1252.29 Debye^2

Average deviation from zero (squared) from each component over time.

>  Total < |M|^2 > = 3653.02 Debye^2

Same thing for total Dipole momentum.

>  Total < |M| >^2 = 12.6108 Debye^2

Average orientation (squared) of the total dipole momentum of my group over 
time.

Is that correct?
Ok, now if i g_analyze -f Mtot.xvg -ee

> Read 4 sets of 1001 points, dt = 5
>
>                                       std. dev.    relative deviation of
>                        standard       ---------   cumulants from those of
> set      average       deviation      sqrt(n-1)   a Gaussian distribition
>                                                       cum. 3   cum. 4
> SS1  -2.201018e+00   3.458052e+01   1.093532e+00      -0.114    0.021
> SS2  -1.652311e+00   3.460259e+01   1.094230e+00       0.016   -0.018
> SS3  -2.244139e+00   3.531650e+01   1.116806e+00      -0.004    0.008
> SS4   5.565348e+01   2.357344e+01   7.454575e-01       0.332   -0.002

Hmm, these values in the first column deviate from the (sqrt) of the above 
ones for the components and total one.

Thanks for any comments.

Btw, in the 3.3 manual, e*nm is stated as dipole moment unit. I checked the 
sourcecode of g_dipoles and afair, the units there are still in Debye.

Cheers
	Martin