Author Topic: How does QuantumATK calculate the kinetic energy?  (Read 255 times)

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Offline narin

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How does QuantumATK calculate the kinetic energy?
« on: August 15, 2022, 19:36 »
Dear Sirs,

How does QuantumATK calculate the kinetic energy? I looked the help page and the manual but couldn't find any formula.

Thanks.

Offline AsifShah

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Re: How does QuantumATK calculate the kinetic energy?
« Reply #1 on: August 16, 2022, 07:01 »
Calculate total energy & look for log file. There will be all energy contributions.

Offline Umberto Martinez

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Re: How does QuantumATK calculate the kinetic energy?
« Reply #2 on: August 16, 2022, 09:03 »
and to extract from an MD, you can use the Kinetic Energy Distribution from the MD analyzer:
https://docs.quantumatk.com/manual/Types/KineticEnergyDistribution/KineticEnergyDistribution.html

Offline filipr

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Re: How does QuantumATK calculate the kinetic energy?
« Reply #3 on: August 16, 2022, 12:11 »
For DFT the kinetic energy is calculated as in any other DFT code (see e.g. https://en.wikipedia.org/wiki/Density_functional_theory and https://en.wikipedia.org/wiki/Kohn%E2%80%93Sham_equations):

T = ⟨T⟩ = ∑n fn ⟨ψn| -ħ2/(2m)∇2n

where fn is the occupation number of the n'th state and |ψn⟩ are the Kohn-Sham states.

Offline narin

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Re: How does QuantumATK calculate the kinetic energy?
« Reply #4 on: August 16, 2022, 18:27 »
Thanks a lot for your replies.