[Wien] question on murnaghan fit
yueqin@mail.ustc.edu.cn
yueqin at mail.ustc.edu.cn
Fri May 25 14:37:15 CEST 2007
Dear Gills,
Thanks very much, the program I post in the previous mail have the parameter to
fit hexagonal systems, I really confused where the problems come from. Well,
thanks again, I really appreciate your help, it helps a lot.
Best Regards
Y.Q. Wang
Gilles Hug wrote:
> Hi,
> To my best knowledge the Murnghan or Birch-Murnaghan EOS is derived
> for cubic system but is not grounded for a general crystallography.
> Other more competent geeks may correct me.
> I tried your dat with my own developped procedure (under Igor see
> www.wavemetrics.com).
> Here is what I found:
> •FuncFit/NTHR=1/TBOX=0 BirchMurnaghan W_coef energy /X=vol /D
> 9 iterations with no decrease in chi square
> fit_energy= BirchMurnaghan(W_coef,x)
> W_coef={358.45,379.62,5.3995,-67028}
> V_chisq= 1.76215e-06;V_npnts= 19;V_numNaNs= 0;V_numINFs= 0;
> V_startRow= 0;V_endRow= 18;
> W_sigma={0.064,0.477,0.00837,0.0449}
> Coefficient values ¡À one standard deviation
> V0 =358.45 ¡À 0.064
> B =379.62 ¡À 0.477
> Bp =5.3995 ¡À 0.00837
> E0 =-67028 ¡À 0.0449
>
> Two comments:
> 1/ B seems quite "strong"
> 2/ Convergence is very verry slow in your case. I don't know why but
> I had to restart the fit a number of times. About 10 X 40 iterations.
> But at the end the chi-square is reasonable (10^-6).
> Although this slow convergence might be due to the initial starting
> point, it should not affect the results but it might screw up wien2k.
> You have to look into details. Fitting wizards here might hepl.
> Regards
> Gilles
>
>
>
> Le 25 mai 07 ¨¤ 13:55, "" <yueqin at mail.ustc.edu.cn> a ¨¦crit :
>
>> Dear Wien users;
>> I try to fit the bulk modulus using the program download here:
>> http://www.fhi-berlin.mpg.de/th/fhi98md/toolkit/
>> since my system is of hexagonal symmetry, however, the output have
>> some "nan"
>> rather than proper quantities. Does anyone have experience on this
>> problem, thanks
>> in advance.
>>
>> Best regards,
>> Y.Q. Wang
>
>> # unit of length = 0.529177 angstroem
>> # energies input in RYDBERGS
>> # unit cell volume = a**3 * 2.233100
>> # a(min)= 5.3106070
>> # a(max)= 5.6399150
>> # points: 100
>> # number of data points: n = 19
>> #----------
>> # i alatt volume E
>> # 1 5.310607 334.457287 -67030.8106070000
>> # 2 5.329989 338.132651 -67030.8176030000
>> # 3 5.349231 341.808005 -67030.8232670000
>> # 4 5.368336 345.483445 -67030.8277190000
>> # 5 5.387305 349.158696 -67030.8310140000
>> # 6 5.406142 352.834073 -67030.8331820000
>> # 7 5.424849 356.509522 -67030.8343210000
>> # 8 5.443427 360.184800 -67030.8344730000
>> # 9 5.461879 363.860068 -67030.8336700000
>> # 10 5.480208 367.535504 -67030.8319440000
>> # 11 5.498415 371.210899 -67030.8294160000
>> # 12 5.516502 374.886250 -67030.8260490000
>> # 13 5.534471 378.561566 -67030.8219570000
>> # 14 5.552324 382.236869 -67030.8171040000
>> # 15 5.570063 385.912187 -67030.8115870000
>> # 16 5.587690 389.587562 -67030.8053670000
>> # 17 5.605207 393.263046 -67030.7985650000
>> # 18 5.622614 396.938277 -67030.7911850000
>> # 19 5.639915 400.613747 -67030.7832080000
>> #----------
>> # alatt0 vol0 (ula**3) b0 (mbar) b0prime e0
>> # 5.4434 360.18480 1.00000 4.00000 0.00000
>> # min: 2.7217 45.02310 0.01000 0.01000
>> # max: 8.1651 1215.62370 10.00000 10.00000
>> #----------
>> # fit by murnaghan equation equation of state
>> #----------
>> #iter, alatt0, vol0 (ula**3), b0 (mbar), b0prime, e0, sq sum, ierr
>> # 20 nan nan nan nan
>> nan nan10
>> # 40 nan nan nan nan
>> nan nan 0
>> #----------
>> # a (a.u.), E
>> #----------
>> 5.31061 nan nan
>> 5.31393 nan nan
>> 5.31726 nan nan
>> 5.32059 nan nan
>> 5.32391 nan nan
>> 5.32724 nan nan
>> 5.33057 nan nan
>> 5.33389 nan nan
>> 5.33722 nan nan
>> 5.34054 nan nan
>> 5.34387 nan nan
>> 5.34720 nan nan
>> 5.35052 nan nan
>> 5.35385 nan nan
>> 5.35718 nan nan
>> 5.36050 nan nan
>> 5.36383 nan nan
>> 5.36715 nan nan
>> 5.37048 nan nan
>> 5.37381 nan nan
>> 5.37713 nan nan
>> 5.38046 nan nan
>> 5.38379 nan nan
>> 5.38711 nan nan
>> 5.39044 nan nan
>> 5.39377 nan nan
>> 5.39709 nan nan
>> 5.40042 nan nan
>> 5.40374 nan nan
>> 5.40707 nan nan
>> 5.41040 nan nan
>> 5.41372 nan nan
>> 5.41705 nan nan
>> 5.42038 nan nan
>> 5.42370 nan nan
>> 5.42703 nan nan
>> 5.43036 nan nan
>> 5.43368 nan nan
>> 5.43701 nan nan
>> 5.44033 nan nan
>> 5.44366 nan nan
>> 5.44699 nan nan
>> 5.45031 nan nan
>> 5.45364 nan nan
>> 5.45697 nan nan
>> 5.46029 nan nan
>> 5.46362 nan nan
>> 5.46695 nan nan
>> 5.47027 nan nan
>> 5.47360 nan nan
>> 5.47692 nan nan
>> 5.48025 nan nan
>> 5.48358 nan nan
>> 5.48690 nan nan
>> 5.49023 nan nan
>> 5.49356 nan nan
>> 5.49688 nan nan
>> 5.50021 nan nan
>> 5.50353 nan nan
>> 5.50686 nan nan
>> 5.51019 nan nan
>> 5.51351 nan nan
>> 5.51684 nan nan
>> 5.52017 nan nan
>> 5.52349 nan nan
>> 5.52682 nan nan
>> 5.53015 nan nan
>> 5.53347 nan nan
>> 5.53680 nan nan
>> 5.54012 nan nan
>> 5.54345 nan nan
>> 5.54678 nan nan
>> 5.55010 nan nan
>> 5.55343 nan nan
>> 5.55676 nan nan
>> 5.56008 nan nan
>> 5.56341 nan nan
>> 5.56674 nan nan
>> 5.57006 nan nan
>> 5.57339 nan nan
>> 5.57671 nan nan
>> 5.58004 nan nan
>> 5.58337 nan nan
>> 5.58669 nan nan
>> 5.59002 nan nan
>> 5.59335 nan nan
>> 5.59667 nan nan
>> 5.60000 nan nan
>> 5.60333 nan nan
>> 5.60665 nan nan
>> 5.60998 nan nan
>> 5.61330 nan nan
>> 5.61663 nan nan
>> 5.61996 nan nan
>> 5.62328 nan nan
>> 5.62661 nan nan
>> 5.62994 nan nan
>> 5.63326 nan nan
>> 5.63659 nan nan
>> 5.63992 nan nan
>>
>>
>> _______________________________________________
>> Wien mailing list
>> Wien at zeus.theochem.tuwien.ac.at
>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>
>
> _______________________________________________
> Wien mailing list
> Wien at zeus.theochem.tuwien.ac.at
> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>
More information about the Wien
mailing list