[Pw_forum] problem to convert Cv (R) to Cv(in J/mol.K)
bramha pandey
pandey.bramha at gmail.com
Thu Feb 2 13:40:42 CET 2012
Dear Stefano de Gironcoli Sir... First thanks to you for your kind response.
When i plot the graph between Cv(R) and T(K) it was showing the good shape
of the Cv vs Tempertaure which was generaly known but difference is that
the scalling of Cv(R) is from 1*10^-7 to 7*10^-7. is it the problem of
sacaling or something else.
Here i am attaching the input file for pw.x and ph.x.
pw.x input File.
&CONTROL
calculation = 'scf' ,
restart_mode = 'from_scratch' ,
outdir = '/' ,
pseudo_dir = '/' ,
prefix = 'aln' ,
tstress = .true. ,
tprnfor = .true. ,
/
&SYSTEM
ibrav = 2,
celldm(1) = 8.97,
nat = 2,
ntyp = 2,
ecutwfc = 28 ,
/
&ELECTRONS
conv_thr = 1.0d-8 ,
mixing_beta = 0.7 ,
/
ATOMIC_SPECIES
Al 26.98000 Al.pz-vbc.UPF
N 14.01000 N.pz-vbc.UPF
ATOMIC_POSITIONS alat
Al 0.000000000 0.000000000 0.000000000
N 0.250000000 0.250000000 0.250000000
K_POINTS automatic
6 6 6 0 0 0
ph.x input file::
phonons at 444
&INPUTPH
outdir = '/' ,
prefix = 'aln' ,
fildyn = 'dyn' ,
ldisp = .true.,
trans = .true.,
nq1=4, nq2=4, nq3=4,
epsil = .false.,
amass(1) = 26.98000,
amass(2) = 14.01000,
iverbosity = 0 ,
tr2_ph = 1.0d-14 ,
/
If the code has read my system has Zero atoms then how can i get rid of
this problem.
Your help in any form is appreciated.
On Thu, Feb 2, 2012 at 5:16 PM, Stefano de Gironcoli <degironc at sissa.it>wrote:
> Dear Bramha Prasad Pandey,
> the question rather seams to me how is it that your phonon DOS
> normalization is zero...
> this means that the code thinks your system has zero atoms.
> stefano
>
>
> On 02.02.2012 11:40, bramha pandey wrote:
> > Sorry to disturbing all of you.
> > But Really i need your's help to understand the the following
> > results. Here i am attaching some more information which is obtained
> > through the F_QHA.X code.
> >
> > # Zero vibration energy: 0.0000000005 (Ry/cell)
> > # Phonon DOS norm : 0.000000 ! 3N for check purpose, N
> > number of atoms in the unit cell
> > # T in K, F_vib in Ry/cell, C_v in R (the universal gas constant by
> > 3N
> > modes), S in k_B
> > #
> > # T E_internal F_vibration Specific heat
> > (C_v) Entropy
> >
> >
> ############################################################################################################
> > 5.00 0.0000000005 0.0000000005 0.0000000000
> > 0.0000000000
> > 10.00 0.0000000005 0.0000000005 0.0000000000
> > 0.0000000000
> > 15.00 0.0000000005 0.0000000005 0.0000000001
> > 0.0000000000
> > 20.00 0.0000000005 0.0000000005 0.0000000002
> > 0.0000000001
> > 25.00 0.0000000005 0.0000000005 0.0000000004
> > 0.0000000001
> > 30.00 0.0000000005 0.0000000005 0.0000000010
> > 0.0000000002
> > 35.00 0.0000000005 0.0000000005 0.0000000020
> > 0.0000000005
> > 40.00 0.0000000005 0.0000000005 0.0000000036
> > 0.0000000008
> > 45.00 0.0000000005 0.0000000005 0.0000000059
> > 0.0000000014
> > 50.00 0.0000000005 0.0000000005 0.0000000090
> > 0.0000000021
> > 55.00 0.0000000005 0.0000000005 0.0000000128
> > 0.0000000032
> > 60.00 0.0000000005 0.0000000005 0.0000000172
> > 0.0000000045
> > 65.00 0.0000000005 0.0000000005 0.0000000223
> > 0.0000000060
> > 70.00 0.0000000006 0.0000000005 0.0000000278
> > 0.0000000079
> > 75.00 0.0000000006 0.0000000005 0.0000000338
> > 0.0000000100
> > 80.00 0.0000000006 0.0000000005 0.0000000402
> > 0.0000000124
> > 85.00 0.0000000006 0.0000000005 0.0000000468
> > 0.0000000150
> > 90.00 0.0000000006 0.0000000005 0.0000000537
> > 0.0000000179
> > 95.00 0.0000000006 0.0000000005 0.0000000607
> > 0.0000000210
> >
> > Now sir question remain same how i will get the Cv value in J/Mol.K
> > from R.?
> >
> > Your valuable help is needed to me.
> >
> > On Wed, Feb 1, 2012 at 9:54 PM, bramha pandey
> > <pandey.bramha at gmail.com> wrote:
> >>
> >>
> >> Hi..Dear QE users
> >>
> >> I have a problem to calculate the Cv value in J/mol.K from Cv(R gas
> >> constant). At 300K, the value of Cv is 0.0000002506 . I multiplied
> >> 0.0000002506 by 3NR(3*2*8.314) which comes 1.25*10^-5 which was very
> >> less compare to experimental Cv value.
> >>
> >> Please someone help me.
> >> Thanks in advanced for your kind help.
> >> --
> >> Thanks and Regards
> >> Bramha Prasad Pandey
> >> Assistant Professor (Electronics and Communication Engg)
> >> GLA Group of Institutions, Mathura.
> >> Ph. No. 08954143009
> >> email id pandey.bramha at gmail.com
> >> bpglaitm at yahoo.co.in
>
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>
--
Thanks and Regards
Bramha Prasad Pandey
Assistant Professor (Electronics and Communication Engg)
GLA Group of Institutions, Mathura.
Ph. No. 08954143009
email id pandey.bramha at gmail.com
bpglaitm at yahoo.co.in
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