No subject

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4.6966380876 * 8.314 =3D 39.048<br />
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(where, Gas constant, R =3D 8.314 J/(mol K) ) and for Silicon N =3D 2, so 3=
N=3D6 modes<br />
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So, Specific heat, C_v=3D 38.761 / 3N =3D 6.5080 J/(mol K)<br />
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Experimentally the Specific heat, C_v of Si at 25 =C2=B0C (~298) is found e=
qual to 9.789 J=C2=B7mol=E2=88=921=C2=B7K=E2=88=921.<br />
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Can anybody could explain the reason behind this huge error in the calculat=
ion of specific heat ?<br />
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Regards<br />
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Amit N.Harode<br />
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CR Labs INDIA<br />
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> Try to compare your calculated phonons and phonon DOS for Si first - > do=
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> come out as obtained e.g. by Giannozzi/De Gironcoli/Pavone/Baroni > PRB 1=
991 ?<br />
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> nicola<br />
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On Mon, 24 May 2010 18:38:31 +0530=EF=BF=BD wrote<br />
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>Dear All<br />
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I have attempted to calculate the specific heat of Si using "F_QHA.x", and =
the calculated Silicon phonon dos=EF=BF=BD as an input.<br />
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(The calculated Si phonon frequencies are in excellent agreement with avail=
able experimental data. )<br />
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As the output of "F_QHA.x", I have obtained the following results, (in QHA.=
out file)<br />
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###########################################################################=
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# 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 />
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###########################################################################=
#################################<br />
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#=EF=BF=BD =EF=BF=BD=EF=BF=BD T=EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=
=BF=BD=EF=BF=BD E_internal=EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD F_vibrati=
on=EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD Specific heat (C_v)=EF=
=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD=EF=BF=BD Entropy<br />
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###########################################################################=
#################################<br />
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=EF=BF=BD 295.00=EF=BF=BD =EF=BF=BD =EF=BF=BD 0.0139740852=EF=BF=BD =EF=BF=
=BD =EF=BF=BD 0.0055747646=EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD=
 =EF=BF=BD=EF=BF=BD 4.6621714979=EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=
=BF=BD 4.4956255367<br />
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 300.00=EF=BF=BD =EF=BF=BD =EF=BF=BD 0.0141222695=EF=BF=BD =EF=BF=BD =EF=BF=
=BD 0.0054311560=EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD=
=EF=BF=BD 4.6966380876=EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD 4.5=
742737931<br />
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 305.00=EF=BF=BD =EF=BF=BD =EF=BF=BD 0.0142715257=EF=BF=BD =EF=BF=BD =EF=BF=
=BD 0.0052850687=EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD=
=EF=BF=BD 4.7298757363=EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD 4.6=
521815403<br />
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 310.00=EF=BF=BD =EF=BF=BD =EF=BF=BD 0.0144218157=EF=BF=BD =EF=BF=BD =EF=BF=
=BD 0.0051365259=EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD=
=EF=BF=BD 4.7619351485=EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD =EF=BF=BD 4.7=
293532915<br />
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###########################################################################=
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