[molpro-user] Two sets of coordinates

[Jacky LIEVIN]

Dear Prof. Chandra,

I agree with the numerous comments of our colleagues.
I would suggest you to adopt Z-matrix coordinates as an alternative to the cartesian coordinates which give you problems. This is a simple way for defining the polar coordinates of an atom with respect to the center of mass of a molecular monomer.
That’s what we did recently for calculating the interaction potential energy surface of the H2O-Ar complex (see JCP 147, 014302 (2017)), which is a very similar system.
Here is the script we used:

r1=1.8096
r2=1.8096
alpha=104.51 degree
alphademi=0.5*alpha degree
mh=1.00782503207
mo=15.99491461956
mh2o=mo+2*mh

x1=r1*cos(alphademi)
y1=r1*sin(alphademi)
x2=r2*cos(alphademi)
y2=r2*sin(alphademi)
xg=mh*(x1+x2)/mh2o
yg=mh*(y1-y2)/mh2o
rg=sqrt(xg**2+yg**2)
beta=acos(xg/rg)

R=4.0
theta=60.0 DEGREE
phi=112.5 DEGREE

geometry={
O
q1 O 3.0
H1 O r1 q1 alphademi
H2 O r2 q1 -alphademi H1 0.0
q2 O rg q1 -beta H1 0.0
q3 q2 3.0 q1 phi h1 0.0
q4 q2 3.0 q3 90.0 h1 0.0
q5 q2 3.0 q3 90.0 q4 90.0
ar q2 R q5 theta q4 90.0
}

Do loops can be implemented for varying R, theta, and phi, and also the internal variables of the monomer if you want.

Best regards

_____________________________________
Prof. Jacky Liévin
Service de Chimie Quantique et Photophysique
Université Libre de Bruxelles, CPi 160/09
50 av F.D. Roosevelt
B-1050 Bruxelles
Belgium
_____________________________________




> Le 24 nov. 2017 à 08:02, Prof. Suresh Chandra <suresh492000 at yahoo.co.in> 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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