No subject

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4.6966380876� * 8.314 = 39.048



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



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



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



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



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Warm Regards



>



Amit N. Harode



>



C R Labs INDIA



>











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<br />
Dear Prof. Eyvaz Isaev<br />
<br />
Thank your explanations!<br />
<br />
On Tue, 25 May 2010 04:26:33 +0530  wrote<br />
>Hi,<br />
> One can see there is excellent agreement with the experimental data. >So,=
 the conversion prescribed in F_QHA.f90 is correct. Please check >again exp=
erimental data for Si (may be it is in cal/mol/K?).<br />
<br />
> You can note that 4.6966*1.985=3D9.32 cal/mol/K, not too far from >experi=
mental data you provided C_v(300K)=3D9.789. Besides, may be >experimental v=
alue is C_p, but not C_v.<br />
<br />
I would like to correct a mistake in last post, for Si,  C (298 K) =3D 19.7=
89 J.mol^{-1}.K^{-1} (and not 9.789 J.mol^{-1}.K^{-1} ) (Sorry for it.)<br =
/>
<br />
For Si, C_p - C_v < 0.004 (Ref.:Flubacher et.al, Phil Mag, 4: 39, 273 =E2=
=80=94 294)<br />
<br />
Also, from PRB, 50, 14587, C_v {~300} ~ 20 J.mol^{-1}.K^{-1}<br />
<br />
<br />
Regards<br />
Amit N. Harode<br />
<br />
<br />
<br />
<br />
Well, let me add that I have found experimental C_v for Al (Phys. Rev. 162,=
 549). From Table II CV(300K)=3D22.91(J/mol/K) and C_v(500K)=3D24.23(J/mol/=
K)<br />
<br />
<br />
<br />