[molpro-user] Two sets of coordinates

[Alexander Mitrushchenkov]

Dear Prof. Chandra,

I am sorry saying that but to me your "problem" does seem trivial. In QC 
codes, users provide coordinates and obtain energy as function of these 
coordinates - what can be more trivial than that? This is user's task to 
provide coordinates he/she wants.

Normally, if the Z-matrix input is used, molpro shifts (all) atoms such 
as origin (which is (0,0,0) in any case) coincides with nuclear center 
of mass (from where I guess 0.16114 comes from), and rotates (whole) 
molecule to intertia axes - these operations do not change the energy. I 
understand that in your case this is not good, as you have fixed 
molecule and move He around. Then you should simply use 'noorient' 
option and provide Cartesian coordinates for all atoms, as easy as this. 
Note that molpro has simple fortran-style input language including 
standard functions, for example to easily explicitly  transform from 
spherical to Carthesian coordinates.

As to what the "interaction energy" He-molecule is, of course this 
depends on how you place the molecule, with origin at center of mass or 
not etc, but this is a physical problem you should address youself and 
has nothing to do with molpro or any other QC code - these codes can not 
know what you call the "interaction energy", they just calculate total 
energy for given set of coordinates of all atoms.

Hope this will be useful for you,

Best wishes,

Alexander


Le 24/11/2017 à 08:02, Prof. Suresh Chandra a écrit :
> Dear Prof. Dr. Werner,
>
> Many thanks for your email. We highly appreciate that you are keeping 
> dialogue open. The owners of MOLPRO are supposed to address the problems.
>
> However, nothing new has emerged from your email,  because of the 
> following. We have sent you two set of coordinates of atoms of H2CS, 
> here called OS1 and OS2, respectively.
>
> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> OS1
> H1      0.000000000    1.765973450   -3.050725593
>                                      H2      0.000000000 
> -1.765973450   -3.050725593
>                                       C       0.000000000 
> 0.000000000   -1.940275913
> S       0.000000000    0.000000000    1.150376265
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> OS2
> H1      0.000000000    1.765967499   -2.745177896
>                                      H2      0.000000000 
> -1.765967499   -2.745177896
>                                       C       0.000000000 
> 0.000000000   -1.634732411
>                                       S       0.000000000 
> 0.000000000    1.455909829
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> in your calculations, you have introduced third set, here called YS, 
> as the following
>
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
> YS
> H1      0.000000000    1.765973450   -3.211867166
> H2      0.000000000   -1.765973450   -3.211867166
> C       0.000000000    0.000000000   -2.101417486
> S       0.000000000    0.000000000    0.989234692
> ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>
> Shifting of coordinates along z-axis has been main concerned in our 
> discussion.  So, from above, we have
>
> z(OS1) + 0.30554 = z(OS2)
>
> z(YS) +0.16114 = z(OS1)
>
> z(YS) + 0.46668 = z(OS2)
>
> Here, 0.46668 = 0.30554 + 0.16114. First, we could not understand how 
> the figure 0.16114 has appeared. Now, you have done two calculations 
> for the following combinations:
>
> (1). H2CS (YS) + He (x, y, z)
>
> (2). H2CS(OS2) + He (x, y, z+0.46668)
>
> The results of these two calculations have to be equal, as in (2) both 
> H2CS and He are shifted by the same amount 0.46668 as compared to (1). 
> It obviously does not show any progress for solving our problem, which 
> we consider not to be trivial.
>
> Submitted for your and others kind consideration.
>
> With regards,
> Prof. Suresh Chandra,
>
> Deputy Director & Professor,
> Amity Centre for Astronomy & Astrophysics,
> Amity Institute of Applied Sciences,
> Amity University, Sector-125,
> NOIDA 201313, U.P., India
>
> Email: schandra2 at amity.edu;
>        suresh492000 at yahoo.co.in
>
> Mob. +91-9818005663, 8368908608
> =========================================
> Alexander von Humboldt Fellow (Germany),
> Former Director, School of Physical Sciences,
> S.R.T.M. University, Nanded (Maharashtra)
>
>
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-- 
Dr. Alexander Mitrushchenkov, IGR
Laboratoire de Modélisation et Simulation Multi Echelle
UMR 8208 CNRS
Université Paris-Est Marne-la-Vallée
5 Bd Descartes
77454 Marne la Vallée, Cedex 2, France

Phone:    +33(0)160957316
Fax:      +33(0)160957320
e-mail:   Alexander.Mitrushchenkov at u-pem.fr

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