Hi,
Let me finish this discussion about? the heat capacity conversion.
Well, I have calculated C_v for graphite with 4 atoms in the unit cell
(hexagonal). Calculated C_v(295K)= 4.0758 (R).? Now converting it to J/mol/K we
get 4.0758*8.3145/4=8.472 J/mol/K which is very good agreement with? 8.517
J/mol/K.
Please pay attention that in this case C_v is per atom, not for the unit cell.
Applying the same procedure for Si we get: 4.6966*8.314/2 = 39.048/2 = 19.524
J/mpl/K that matches very well 19.789 you updated (see below).
> I would like to correct a mistake in last post, for Si, C (298 K) =
> 19.789 J.mol^{-1}.K^{-1} (and not 9.789 J.mol^{-1}.K^{-1} ) (Sorry for > it.)
> Also, from PRB, 50, 14587, C_v {~300} ~ 20 J.mol^{-1}.K^{-1}
> For Si, C_p - C_v < 0.004 (Ref.:Flubacher et.al, Phil Mag, 4: 39, 273 > ? 294)
Yes, sure there will be not too much difference in between C_p and C_v at room
temperature.
> Can anybody could explain the reason behind this huge error in the
> calculation of specific heat ?
Hopefully, now it is explained. Just be sure in comparison with an experimental
data whether C_v(Exp) is for per atom or per cell or formula unit, etc.
Bests,
Eyvaz
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Prof. Eyvaz Isaev,
Department of Physics, Chemistry, and Biology (IFM), Linkoping University,
Sweden
Theoretical Physics Department, Moscow State Institute of Steel & Alloys,
Russia,
isaev at ifm.liu.se, eyvaz_isaev at yahoo.com
