### Author Topic: Adsorption energy  (Read 126 times)

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#### khariyahA

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##### Adsorption energy
« on: November 17, 2021, 05:17 »
Hi Sir,

I am currently studying about GNR gas sensor and i wanted to find the adsorption energy. I need advice and want to clarify the procedure.

Procedure:
1. i build my structure --> run calculator and optimize geometry.
2. i repeat the structure along c direction and attach the gas at one of the atom (let say H2 gas at carbon).
3. send to calculator, add bandstructure, dos and total energy. I use LDA, FHI for pseudopotential and doublezetapolarized for basis set.

Is the procedure above correct Sir ? and Sir, is it acceptable for the value of total energy if it is too big ?

#### mlee

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##### Re: Adsorption energy
« Reply #1 on: November 17, 2021, 13:14 »
In the LCAO calculator, the adsorption energy shows better accuracy with Counterpoise correction. When you open the calculator, you can see the Counterpoise section and add it in the script as ticking and selecting the adsorbent.

#### khariyahA

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##### Re: Adsorption energy
« Reply #2 on: November 18, 2021, 02:29 »
Thankyou Sir for the reply. I will try it

#### khariyahA

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##### Re: Adsorption energy
« Reply #3 on: November 18, 2021, 03:58 »
Hi Sir,

I have include the counterpoise section and select the H2 gas adsorbent. Below is the attachment result of total energy i have obtained. Before that, i want to clarify, the adsorption energy is the total energy, right Sir ?  The total energy i get is still way too big, is it acceptable Sir ? Im confused. From the papers i have read, the adsorption energy is low.

Sir, i would greatly appreciate if you can give me some advice regarding this. Thankyou

#### dprai

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##### Re: Adsorption energy
« Reply #4 on: November 18, 2021, 08:14 »
Which ATK version are you using?

#### khariyahA

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##### Re: Adsorption energy
« Reply #5 on: November 18, 2021, 08:21 »
Hi dprai,

Im using latest version, S-2021.06.

#### dprai

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##### Re: Adsorption energy
« Reply #6 on: November 18, 2021, 08:31 »
There is a formula for adsorption energy calculation. The one you obtained is the CP corrected total energy of the complex.
For adsorption energy do,  total energy of the complex - (total energy of the host + total energy of the gas)

#### khariyahA

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##### Re: Adsorption energy
« Reply #7 on: November 18, 2021, 08:52 »
Thankyou dprai for the reply

Is that mean i need to do manual calculation using the formula ? Im still not clear, do i need to do another separate simulation to get ( the total energy of host + total energy of the the gas ) ?

#### dprai

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##### Re: Adsorption energy
« Reply #8 on: November 18, 2021, 09:20 »
Yes. You have to calculate the total energy of the host material and total energy of the molecules separately. Please check your inbox. I have asked you some query.

#### dprai

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##### Re: Adsorption energy
« Reply #9 on: November 18, 2021, 09:58 »