How to calculate the free energy from the nwchem output file

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Hi,

I would like to know how to calculate the Free energy change from the nwchem output file.

Thanks

  • Huub Forum:Admin, Forum:Mod, NWChemDeveloper, bureaucrat, sysop
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Hi Mhiranya,

Could you say something more about what you are doing? Are you running dynamics, or do you just want to calculate the free energy at two reaction end points? I need a little more information to be able to give you an answer that is appropriate for your study.

Huub

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Huub,

No, I'm not running dynamics, I'm studying about isomers of Rh catalyst. I want to calculate their free energy change.

So, this is the part of the output thermodynamic parameters, however, total enthalpy is missing here.

Hope you can help me with this.

Thanks
       Vibrational analysis via the FX method 
--- with translations and rotations projected out ---
--- via the Eckart algorithm ---
Projected Nuclear Hessian trans-rot subspace norm:1.2699D-33
(should be close to zero!)


From the projected analysis
The Zero-Point Energy (Kcal/mol) = 99.33560788

center of mass
--------------
x = 0.07031235 y = -0.10235627 z = 0.03349458

moments of inertia (a.u.)
------------------
2942.527422606949 16.957400854026 -31.017758287500
16.957400854026 1815.031657939912 44.968030875314
-31.017758287500 44.968030875314 3243.687056532644

Rotational Constants
--------------------
A= 0.033199 cm-1 ( 0.047764 K)
B= 0.020478 cm-1 ( 0.029462 K)
C= 0.018534 cm-1 ( 0.026665 K)


Temperature                      =   298.15K
frequency scaling parameter = 1.0000

Zero-Point correction to Energy  =   99.258 kcal/mol  (  0.158178 au)
Thermal correction to Energy = 108.841 kcal/mol ( 0.173449 au)
Thermal correction to Enthalpy = 109.433 kcal/mol ( 0.174393 au)

Total Entropy                    =  125.807 cal/mol-K
- Translational = 42.477 cal/mol-K (mol. weight = 253.9490)
- Rotational = 31.213 cal/mol-K (symmetry # = 1)
- Vibrational = 52.117 cal/mol-K

Cv (constant volume heat capacity) =   52.354 cal/mol-K
- Translational = 2.979 cal/mol-K
- Rotational = 2.979 cal/mol-K
- Vibrational = 46.395 cal/mol-K


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