[molpro-user] To understand the reason for difference betweeen two outputs for the same situation developed by MOLPRO
João Brandão
jbrandao at ualg.pt
Tue Nov 14 15:38:28 CET 2017
Dear Prof. Suresh Chandra
*Sorry, but the statement:* /"When the coordinates are different, the
bond lengths and angles have to be different." /*Is wrong.
There is no geometry rule to support it.*
I have computed the distances for you:
1 H1 1 0.000000000 1.765967499 -2.745177896
2 H2 1 0.000000000 -1.765967499 -2.745177896
3 C 6 0.000000000 0.000000000 -1.634732411
4 S 16 0.000000000 0.000000000 1.455909829
rhh rh1c
rh2c rh1s rh2s rcs
3.531934998 2.086080148 2.086080148 4.557167901
4.557167901 3.09064224
1 H1 1 0.000000000 1.765973450 -3.050725593
2 H2 1 0.000000000 -1.765973450 -3.050725593
3 C 6 0.000000000 0.000000000 -1.940275913
4 S 16 0.000000000 0.000000000 1.150376265
rhh rh1c
rh2c rh1s rh2s rcs
3.5319469 2.086087419 2.086087419 4.557183236
4.557183236 3.090652178
From one of the triangle rules: /"If the 3 sides are equal, the
triangles are equal",/ we can also say that all the angles are the same.
*Looking carefully you just have a translation of -0.305548 in the zz
axis, and the centre of mass is not the same in both results.
*
So you got the same result... And the He atom should be located at
different *relative* positions.
Best regards
João Brandão
Em 14-11-2017 07:39, Prof. Suresh Chandra escreveu:
> Dear Dr. Brandao,
>
> In the two outputs, the coordinates of atoms are quite different. In
> general, the coordinates are with respect to the origin at the
> center-of-mass of the molecule. When the coordinates are different,
> the bond lengths and angles have to be different. Our aim is to
> calculate interaction potential between the molecule of interest (say,
> H2CS) and colliding partner He atom. The He atom would be placed at
> various positions relative to the center-of mass of the H2CS. In the
> event of different coordinates of constituent atoms, the interaction
> potential would be different and whole aim would be spoiled.
>
> 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 yhoo.co.in
>
> Mob. +91-9818005663, 8368908608
> =========================================
> Alexander von Humboldt Fellow (Germany),
> Former Director, School of Physical Sciences,
> S.R.T.M. University, Nanded (Maharashtra)
>
>
> On Monday, 13 November 2017 9:10 AM, João Brandão <jbrandao at ualg.pt>
> wrote:
>
>
> Dear Suresh Chandra
>
> Have you computed the distances and angles?
> At first sight, the distances between the atoms seem to be the same
> and you simple have a translation/rotation of the system.
>
> Best regards
>
> João Brandão
>
> Em 10-11-2017 06:50, Prof. Suresh Chandra escreveu:
>> Dear Friends,
>>
>> We have optimized H2CS on 21 September 2017 and on 1 April 2014 with
>> the help of
>> MOLPRO using the same basis-set and the same method, but we got two
>> different results,
>> attached herewith (where lines are deleted in the text; one can ask
>> for complete output). For example,
>> in the output file h2cs_opt-fixed.out, the optimized coordinates are:
>>
>> Atomic Coordinates
>>
>> Nr Atom Charge X Y Z
>>
>> 1 H1 1.00 0.000000000 1.765967499 -2.745177896
>> 2 H2 1.00 0.000000000 -1.765967499 -2.745177896
>> 3 C 6.00 0.000000000 0.000000000 -1.634732411
>> 4 S 16.00 0.000000000 0.000000000 1.455909829
>>
>> On the other side, the optimized coordinates in the output file
>> H2CS_opt2.out are:
>>
>> Atomic Coordinates
>>
>> Nr Atom Charge X Y Z
>>
>> 1 H1 1.00 0.000000000 1.765973450 -3.050725593
>> 2 H2 1.00 0.000000000 -1.765973450 -3.050725593
>> 3 C 6.00 0.000000000 0.000000000 -1.940275913
>> 4 S 16.00 0.000000000 0.000000000 1.150376265
>>
>> There is large difference. Could you please suggest me some reason
>> for the
>> difference between the two outputs.
>>
>> 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 <mailto:schandra2 at amity.edu>;
>> suresh492000 at yhoo.co.in <mailto:suresh492000 at yhoo.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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> --
> João Brandão
> Dep. de Química e Farmácia
> Universidade do Algarve
> 8005-139 Faro, Portugal
> e-mail:jbrandao at ualg.pt <mailto:jbrandao at ualg.pt>
>
>
--
João Brandão
Dep. de Química e Farmácia
Universidade do Algarve
8005-139 Faro, Portugal
e-mail: jbrandao at ualg.pt
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