[gmx-users] heat capacity in 4.5.3 and 4.0.7

Elisabeth katesedate at gmail.com
Sun Mar 27 19:23:50 CEST 2011

>  Thanks David for replying me. I appreciate your attention to comment on
>> the following short inquiries.
>> 1- g_energy says:
>> you will need to give the number of constraints per molecule –nconstr and
> for water this is 3.  Can you elaborate on how to set this option. When
constraints= all-bonds how to set -nconstr for a simlpe alkane for instance?
It refers to number of atoms of each molecule on which constraints are

>> 2- Aside from heat capacities, does g_energy report the following
>> properties correctly?
>> Thermal expansion coeff. (NPT): Enthalpy, Vol, Temp
>> Isothermal compressibility:     Vol, Temp
>> Adiabatic bulk modulus:         Vol, Temp
3- Since volume appears for calculation of the above properties , does this
>> imply ONLY NPT results in these properties? (because in NPT g_energy reports
>> "volume").
>> 4- For thermal expansion: I read one of your earlier messages saying that
>> enthalpy = Etot(total energy) +pv,  [where Etot is potential+kinetic (in
>> g_energy list)]
>             and for pv , take ref_p and not measure p (that g_energy
reports). If the system is equilibrated to ref_p, then why not taking pv
from g_energy? you mean product of pv that        g_energy gives is not

>> Many thanks for you time!
>> Best,
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