Thermodynamic equipartition of energy theorem - application to life

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SUMMARY

The discussion centers on the application of the equipartition of energy theorem to a simulation of water molecules (SPC/E) at 320K, specifically addressing the energy barrier of 4kT that water molecules must overcome to pass through a barrier. Each water molecule possesses 3 translational degrees of freedom, leading to an average energy of 3/2kT. Additionally, the presence of ions in the system is noted, with their average energy being 3/2kT as well. The impact of pressure and fluid interactions is also highlighted, suggesting the use of the Maxwell-Boltzmann Distribution for estimating molecular behavior.

PREREQUISITES
  • Understanding of the equipartition of energy theorem
  • Familiarity with SPC/E water model
  • Knowledge of Maxwell-Boltzmann Distribution
  • Basic principles of molecular simulation
NEXT STEPS
  • Research the degrees of freedom in molecular dynamics simulations
  • Explore the implications of pressure on fluid dynamics
  • Learn about the Maxwell-Boltzmann Distribution in detail
  • Investigate the energy calculations for ions in molecular systems
USEFUL FOR

This discussion is beneficial for molecular simulation researchers, physical chemists, and anyone interested in the thermodynamic properties of fluids and the behavior of molecules under energy barriers.

trelek2
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hi, I'm simulating a system of molecules (water) and in order to pass through a barrier they have to overcome an energy barrier of 4kT. What is the probability of a water molecule passing the barrier or perhaps what is the average energy of a water molecule in my system?

I know it's 1/2 *kT per each degree of freedom, but how many degrees of freedom do my water molecules have? (I'm simulating at 320K, water molecules are SPC/E).

Oh, and i also have ions in my system. What is their average energy? 3/2kT?

Thanks for any insight!
 
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Did you mean degrees of freedom per water molecule?

http://www.pha.jhu.edu/~broholm/l37/node5.html

Perhaps you should also take into consideration the pressure and pressure difference in the water?
 
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It's not that trivial for fluids due to interactions. You can basically look at Maxwell-Boltzmann Distribution which deals with something very similar for gases, and you might be able to use it as a rough estimate for water, but don't expect anything particularly good out of it.
 

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