No subject

4.6966380876  * 8.314 = 39.048
(where, Gas constant, R = 8.314 J/(mol K) ) and for Silicon N = 2, so 3N=6 modes

So, Specific heat, C_v= 38.761 / 3N = 6.5080  J/(mol K)

Experimentally the Specific heat, C_v of Si at 25 °C (~298) is found equal to 9.789 J·mol−1·K−1. 

Can anybody could explain the reason behind this huge error in the calculation of specific heat ?

Warm Regards
Amit N. Harode
C R Labs INDIA

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Dear All<br />
<br />
I have attempted to calculate the specific heat of Si using "F_QHA.x", and =
the calculated Silicon phonon dos  as an input.<br />
(The calculated Si phonon frequencies are in excellent agreement with avail=
able experimental data. )<br />
<br />
As the output of "F_QHA.x", I have obtained the following results, (in QHA.=
out file)<br />
<br />
###########################################################################=
#################################<br />
<br />
# T in K, F_vib in Ry/cell, C_v in R (the universal gas constant by 3N mode=
s), S in k_B<br />
###########################################################################=
#################################<br />
#   T         E_internal        F_vibration          Specific heat (C_v)   =
    Entropy<br />
###########################################################################=
#################################<br />
:<br />
:<br />
  295.00      0.0139740852      0.0055747646           4.6621714979        =
  4.4956255367<br />
 300.00      0.0141222695      0.0054311560           4.6966380876         =
 4.5742737931<br />
 305.00      0.0142715257      0.0052850687           4.7298757363         =
 4.6521815403<br />
 310.00      0.0144218157      0.0051365259           4.7619351485         =
 4.7293532915<br />
:<br />
:<br />
:<br />
###########################################################################=
#################################<br />
<br />