Dear Feff Users,
first of all I must admit that I am a total beginner and probably
there are some things which I don’t understand very well.
I need to make XANES and DOS calculations for K-edge of sulfur and
then compare them with experiment. I use feff 8.4.
First, I started from inorganic compounds such as CdS. I generated
feff.inp file in ATOMS and first run feff with default values
(generated by ATOMS). The fit wasn’t perfect so I started to change
parameters-FMS and SCF but there was so significant improvement. I can
only add that others fit are even worse. My question is which
parameter I should change or which card should I add to make XANES
calculations better? Maybe you can recommend any paper?
The second question is about DOS calculations. I took the pDOS
functions for each atom, set Fermi level from ldosNN files, but the
main peaks are below this level and I don’t have any correspondence
with XANES spectrum. For other compounds I have the same problem.
Should I add any extra shift?
I will be grateful for your advice.
Regards
Joanna Czapla
I add the original feff.inp file generated by ATOMS:
* This feff8 input file was generated by WebAtoms 1.8 (Atoms 3.0beta10)
* Atoms written by and copyright (c) Bruce Ravel, 1998-2001
TITLE name: CdS (greenockite) (cubic zinc sulfide structure)
TITLE formula: CdS
TITLE sites: Cd1,S1
TITLE refer1: wyckoff 1,III,110
TITLE refer2:
TITLE schoen:
TITLE notes1: cubic zinc sulfide structure
* S K edge energy = 2472.0 eV
EDGE K
S02 1.0
* pot xsph fms paths genfmt ff2chi
CONTROL 1 1 1 1 1 1
PRINT 1 0 0 0 0 0
*** ixc=0 means to use Hedin-Lundqvist
* ixc [ Vr Vi ]
EXCHANGE 0
*** Radius of small cluster for
*** self-consistency calculation
*** A sphere including 2 shells is
*** a good choice
*** l_scf = 0 for a solid, 1 for a molecule
* r_scf [ l_scf n_scf ca ]
SCF 4.0
*** Upper limit of XANES calculation.
*** This *must* be uncommented to
*** make Feff calculate full multiple
*** scattering rather than a path expansion
* kmax [ delta_k delta_e ]
XANES 4.0
*** Radius of cluster for Full Multiple
*** Scattering calculation
*** l_fms = 0 for a solid, 1 for a molecule
* r_fms l_fms
FMS 5.54240 0
*** Energy grid over which to calculate
*** DOS functions
* emin emax eimag
LDOS -30 20 0.1
*** for EXAFS: RMAX 8.0 and uncomment
*** the EXAFS card
RPATH 0.1
*EXAFS 20
POTENTIALS
* ipot Z element l_scmt l_fms stoichiometry
0 16 S 2 2 0.001
1 48 Cd 3 3 4
2 16 S 2 2 4
ATOMS * this list contains 87 atoms
* x y z ipot tag distance
0.00000 0.00000 0.00000 0 S1 0.00000 0
-1.45450 1.45450 1.45450 1 Cd1 2.51927 1
1.45450 -1.45450 1.45450 1 Cd1 2.51927 2
1.45450 1.45450 -1.45450 1 Cd1 2.51927 3
-1.45450 -1.45450 -1.45450 1 Cd1 2.51927 4
2.90900 2.90900 0.00000 2 S1 4.11395 5
-2.90900 2.90900 0.00000 2 S1 4.11395 6
2.90900 -2.90900 0.00000 2 S1 4.11395 7
-2.90900 -2.90900 0.00000 2 S1 4.11395 8
2.90900 0.00000 2.90900 2 S1 4.11395 9
-2.90900 0.00000 2.90900 2 S1 4.11395 10
0.00000 2.90900 2.90900 2 S1 4.11395 11
0.00000 -2.90900 2.90900 2 S1 4.11395 12
2.90900 0.00000 -2.90900 2 S1 4.11395 13
-2.90900 0.00000 -2.90900 2 S1 4.11395 14
0.00000 2.90900 -2.90900 2 S1 4.11395 15
0.00000 -2.90900 -2.90900 2 S1 4.11395 16
4.36350 1.45450 1.45450 1 Cd1 4.82403 17
1.45450 4.36350 1.45450 1 Cd1 4.82403 18
-4.36350 -1.45450 1.45450 1 Cd1 4.82403 19
-1.45450 -4.36350 1.45450 1 Cd1 4.82403 20
1.45450 1.45450 4.36350 1 Cd1 4.82403 21
-1.45450 -1.45450 4.36350 1 Cd1 4.82403 22
-4.36350 1.45450 -1.45450 1 Cd1 4.82403 23
-1.45450 4.36350 -1.45450 1 Cd1 4.82403 24
4.36350 -1.45450 -1.45450 1 Cd1 4.82403 25
1.45450 -4.36350 -1.45450 1 Cd1 4.82403 26
-1.45450 1.45450 -4.36350 1 Cd1 4.82403 27
1.45450 -1.45450 -4.36350 1 Cd1 4.82403 28
5.81800 0.00000 0.00000 2 S1 5.81800 29
-5.81800 0.00000 0.00000 2 S1 5.81800 30
0.00000 5.81800 0.00000 2 S1 5.81800 31
0.00000 -5.81800 0.00000 2 S1 5.81800 32
0.00000 0.00000 5.81800 2 S1 5.81800 33
0.00000 0.00000 -5.81800 2 S1 5.81800 34
-4.36350 4.36350 1.45450 1 Cd1 6.34002 35
4.36350 -4.36350 1.45450 1 Cd1 6.34002 36
-4.36350 1.45450 4.36350 1 Cd1 6.34002 37
-1.45450 4.36350 4.36350 1 Cd1 6.34002 38
4.36350 -1.45450 4.36350 1 Cd1 6.34002 39
1.45450 -4.36350 4.36350 1 Cd1 6.34002 40
4.36350 4.36350 -1.45450 1 Cd1 6.34002 41
-4.36350 -4.36350 -1.45450 1 Cd1 6.34002 42
4.36350 1.45450 -4.36350 1 Cd1 6.34002 43
1.45450 4.36350 -4.36350 1 Cd1 6.34002 44
-4.36350 -1.45450 -4.36350 1 Cd1 6.34002 45
-1.45450 -4.36350 -4.36350 1 Cd1 6.34002 46
5.81800 2.90900 2.90900 2 S1 7.12557 47
-5.81800 2.90900 2.90900 2 S1 7.12557 48
2.90900 5.81800 2.90900 2 S1 7.12557 49
-2.90900 5.81800 2.90900 2 S1 7.12557 50
5.81800 -2.90900 2.90900 2 S1 7.12557 51
-5.81800 -2.90900 2.90900 2 S1 7.12557 52
2.90900 -5.81800 2.90900 2 S1 7.12557 53
-2.90900 -5.81800 2.90900 2 S1 7.12557 54
2.90900 2.90900 5.81800 2 S1 7.12557 55
-2.90900 2.90900 5.81800 2 S1 7.12557 56
2.90900 -2.90900 5.81800 2 S1 7.12557 57
-2.90900 -2.90900 5.81800 2 S1 7.12557 58
5.81800 2.90900 -2.90900 2 S1 7.12557 59
-5.81800 2.90900 -2.90900 2 S1 7.12557 60
2.90900 5.81800 -2.90900 2 S1 7.12557 61
-2.90900 5.81800 -2.90900 2 S1 7.12557 62
5.81800 -2.90900 -2.90900 2 S1 7.12557 63
-5.81800 -2.90900 -2.90900 2 S1 7.12557 64
2.90900 -5.81800 -2.90900 2 S1 7.12557 65
-2.90900 -5.81800 -2.90900 2 S1 7.12557 66
2.90900 2.90900 -5.81800 2 S1 7.12557 67
-2.90900 2.90900 -5.81800 2 S1 7.12557 68
2.90900 -2.90900 -5.81800 2 S1 7.12557 69
-2.90900 -2.90900 -5.81800 2 S1 7.12557 70
-7.27250 1.45450 1.45450 1 Cd1 7.55780 71
-1.45450 7.27250 1.45450 1 Cd1 7.55780 72
7.27250 -1.45450 1.45450 1 Cd1 7.55780 73
1.45450 -7.27250 1.45450 1 Cd1 7.55780 74
4.36350 4.36350 4.36350 1 Cd1 7.55780 75
-4.36350 -4.36350 4.36350 1 Cd1 7.55780 76
-1.45450 1.45450 7.27250 1 Cd1 7.55780 77
1.45450 -1.45450 7.27250 1 Cd1 7.55780 78
7.27250 1.45450 -1.45450 1 Cd1 7.55780 79
1.45450 7.27250 -1.45450 1 Cd1 7.55780 80
-7.27250 -1.45450 -1.45450 1 Cd1 7.55780 81
-1.45450 -7.27250 -1.45450 1 Cd1 7.55780 82
-4.36350 4.36350 -4.36350 1 Cd1 7.55780 83
4.36350 -4.36350 -4.36350 1 Cd1 7.55780 84
1.45450 1.45450 -7.27250 1 Cd1 7.55780 85
-1.45450 -1.45450 -7.27250 1 Cd1 7.55780 86
END
2010/5/21
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Today's Topics:
1. fitting (mohamed sobhy) 2. update error in Windows 7 (pkraal@geo.uu.nl) 3. Re: update error in Windows 7 (Laurent Menard) 4. Re: update error in Windows 7 (Bryan Gauntt)
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Message: 1 Date: Thu, 20 May 2010 14:14:18 -0700 (PDT) From: mohamed sobhy
To: ifeffit@millenia.cars.aps.anl.gov Subject: [Ifeffit] fitting Message-ID: <725080.73390.qm@web50302.mail.re2.yahoo.com> Content-Type: text/plain; charset="us-ascii" Dear all thanks for your help and explanation about the background I fitted my data after removing the background and in the attached file I got this fitting, although all the values are good but I think the coordination number should be less than 8 (for the first shell) due to irradiation. So how can I get the right coordination number? How to improve the fitting of second shell? thanks
participants (1)
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Joanna Czapla