Is it possible in CP2K to determine Individual Bond Dissociation Energy for any Bond in organic molecules?

[Susmita/Rajib]

Hello, Illustrious Members!
I have a query:
Let us assume one is in possession of a particular named organic reaction.
In that reaction a set of reactants change into a set of products.
It is very easy to observe in those named reactions as to which bonds
have broken down to form other newer bonds.
Is it possible in CP2K to determine Individual Bond Dissociation
Energy for any such Bond of those reactants and products?
Regards
Rajib

[Vladimir Rybkin]

Dear Rajib,

1) a real reaction (if it's not a dissociation of a diatomic molecule) is never reduced to breaking/formation of bonds, but is always followed by structure rearrangement;
2) yes, it's possible calculate the reaction energy, which is an observable, with CP2K (as well as with any other molecular simulation code) if reactants and products are treated consistently (same level of theory, full structure relaxation);
3) real reaction energy is NOT the individual bond dissociation energy. The question of interpretation of this number is entirely the responsibility of the user, since bond dissociation energy is not a rigorous quantum-mechanical concept;
4) individual bond energy can also be calculated if all degrees of freedom except for this bond are frozen. Whether this number has any meaning is again at the responsibility of the user.

Yours,

Vladimir

пятница, 2 июня 2017 г., 7:41:02 UTC+2 пользователь Susmita/Rajib написал:

[Susmita/Rajib]

Dear Prof. Vladimir Rybkin,
Thank you for responding so quickly to my email!
Sir, I am very much aware that  Bond Dissociation Energy of individual
bonds is a kind of reductionism I have indulged in, while the fact is
that the Energy for a particular bond dissociation of a definite
quantity of molecules is distributed along a Bell Curve for that
particular unit of molecules.
The simplification was required to convey the kind of information we'd
require for our studies.

I am thankful that the need was conveyed and was understood.

You said:
... bond dissociation energy is not a rigorous quantum-mechanical concept ...

Which means CP2K is capable of a rigorous QM concept. What is the
level of that rigorous QM application, Sir?

You also said:
...  individual bond energy can also be calculated if all degrees of
freedom except for this bond are frozen ...
Which means CP2K is capable of this capability also? I am enthused, Sir.

I will proceed to search for the package for Debian/Knoppix and if I
need any information I will contact the forum.

In the meanwhile, will it be possible for me to peruse some snapshots of the software? Some images of the GUI?
Regards,
Rajib

[Susmita/Rajib]

             (Any knowledgeable group-member is free to answer!),

Dear Prof. Rybkin
I am still awaiting your reply for the part:
In the meanwhile, will it be possible for me to peruse some snap-/screen-shots
of the software? Some snap-/screen-shot images of the GUI?
Perhaps you overlooked this question at the end of my email.
Sir, I also want to ask if cp2k is interacted with via terminal only, i.e.,
command-line driven, and doesn't have a GUI?
Regards,
Rajib

...

[Susmita/Rajib]

Dear All,
I will provide with a specific example:
Say, for Williamson's Ether Synthesis, with the reaction of sodium
ethoxide with chloroethane to form diethyl ether and sodium chloride.
Here, I would need to know the average BDEs of the bond between Sodium
and Oxygen in socium ethozide, that between carbon and chlorine in
chloroethane, and that between Sodium and Chlorine in Sodium Chloride
separately from the software itself.
Could I ''also'' get to look at a few png files of some molecules? Of
some particular bonded atoms in a molecule?
I hope I have explained myself clearly.
Regards,
Rajib

[Vladimir Rybkin]

Dear Susmita/Rajib,

1) most questions you are asking has nothing to do with CP2K specifically, but are rather general issues of computational/quantum chemistry. Thus, I advise you to go through any basic book on the subject (e.g. Jensen's "Introduction to computational chemistry"), as answering your questions in two words is impossible and is not directly related to CP2K. You will learn about the concepts and existing methods, which will help you to pose specific questions and navigate through the manual;

2) there is no GUI, at least, the one officially maintained by the developers and making it is not a near-future plan;

3) for the examples of research possible with CP2K please visit the site: https://www.cp2k.org/science

And I am not a professor.

Yours,

Vladimir

понедельник, 5 июня 2017 г., 19:43:22 UTC+2 пользователь Susmita/Rajib написал:

[Susmita/Rajib]

Dear All, particularly, Dr. Rybkin,
Please refer to the subject of my email.
I just used Williamson's Ether Synthesis as an example.
I wish to do this for any reaction, provided they are experimentally possible.
Manually calculating BDE for any arbitrary bond is difficult, so I
wish to have it done by software, like clicking on any bond and
finding the BDE for the said bond.
But then. that cp2k is not GUI I learnt rather late.
So I believe I won't be installing the package after all!
Thank you for making my stay on this forum uneventfully safe.
Regard,
Rajib