[Ifeffit] Problem reproducing spectrum for Ti complex (Josh Kas)
joshua jason kas
hebhop at u.washington.edu
Wed Sep 3 14:29:12 CDT 2008
Hi Janine,
I think that distortions could play a role here. When I shift the central
Ti atom by 0.1 angstroms in plane (perpendicular to the Cl bonds) to
break the planar symmetry, I get a clear double pre-edge peak. 0.1
angstroms may be a bit large but
0.05 is certainly not, since 0.003 angstroms**2 is a very reasonable value
for sigma**2. You could also estimate the distortion if you have more
information about the debye waller factors, or even better, you could
perform a molecular dynamics simulation and do a configurational average
of the XANES spectra from snapshots. Below is
the feff.inp file that I used. You might want to play with
shifting the Ti atom in different directions too.
Cheers,
Josh Kas
TITLE TiPcCl2 molecule Geom1acc
CONTROL 1 1 1 1 1 1
PRINT 5 0 0 0 0 0
FMS 9.0 1
*1 appropriate for molecules (wiki)
MULTIPOLE 2
*Dipole and quadrupole
EXCHANGE 0 0 0 0
*Dirac Hara, -1eV Fermi level shift, -3 broadening
SCF 8.0 1
*includes second coordination shell
XANES 6.0 0.03 0.001
AFOLP 1.2
CRITERION 0 0
RPATH 0.1
SIG2 0.005
* emin emax eimag
* LDOS -20 20 0.2
POTENTIALS
*absorbing atom is the Ti
*ipot z tag
0 22 Ti
1 6 C
2 7 N
3 1 H
4 17 Cl
ATOMS
0 0.1 0 0 0
-0.00040276 -2.1184 -0.28392 2 2.13734
-2.11835 0.00044201 -0.284329 2 2.13734
0.00049691 2.11839 -0.284036 2 2.13734
2.11844 -0.00045764 -0.283627 2 2.13734
-0.00040584 6.782e-05 2.45003 4 2.45003
0.00040523 -6.766e-05 -2.45005 4 2.45005
-1.14859 2.9207 -0.359915 1 3.159
-1.14983 -2.92023 -0.359755 1 3.159
-2.92016 1.14988 -0.36016 1 3.159
-2.92065 -1.14866 -0.360097 1 3.159
1.14871 -2.92072 -0.359374 1 3.159
1.14995 2.92021 -0.359534 1 3.159
2.92028 -1.1499 -0.359129 1 3.159
2.92077 1.14864 -0.359192 1 3.159
-2.49915 2.50027 -0.371632 2 3.5546
-2.50021 -2.49922 -0.371494 2 3.5546
2.49928 -2.50029 -0.370665 2 3.5546
2.50034 2.4992 -0.370803 2 3.5546
-0.692606 4.24003 -0.468777 1 4.32173
-0.694406 -4.23976 -0.468544 1 4.32173
-4.23967 0.694471 -0.469267 1 4.32173
-4.23997 -0.692696 -0.469229 1 4.32173
0.692761 -4.24006 -0.468314 1 4.32173
0.694562 4.23974 -0.468547 1 4.32173
4.23983 -0.694497 -0.467823 1 4.32173
4.24012 0.69267 -0.467862 1 4.32173
-1.42292 5.42169 -0.582346 1 5.63547
-1.42522 -5.42112 -0.582048 1 5.63547
-5.42101 1.4253 -0.582898 1 5.63547
-5.42161 -1.42303 -0.58282 1 5.63547
1.42311 -5.42172 -0.581576 1 5.63547
1.42541 5.42109 -0.581873 1 5.63547
5.4212 -1.42533 -0.581023 1 5.63547
5.42181 1.423 -0.581101 1 5.63547
-2.50314 5.41265 -0.586151 3 5.99217
-2.50544 -5.41162 -0.585854 3 5.99217
-5.41151 2.50552 -0.586554 3 5.99217
-5.41257 -2.50326 -0.586416 3 5.99217
2.50334 -5.41269 -0.585024 3 5.99217
2.50564 5.41159 -0.585321 3 5.99217
5.4117 -2.50555 -0.584622 3 5.99217
5.41277 2.50322 -0.584759 3 5.99217
-0.705001 6.62658 -0.692551 1 6.69987
-0.707815 -6.62632 -0.692187 1 6.69987
-6.62618 0.707911 -0.693369 1 6.69987
-6.62648 -0.705135 -0.69333 1 6.69987
0.70523 -6.62662 -0.691953 1 6.69987
0.708044 6.62628 -0.692316 1 6.69987
6.62641 -0.707949 -0.691134 1 6.69987
6.62671 0.705096 -0.691173 1 6.69987
-1.23945 7.56123 -0.780998 3 7.70184
-1.24266 -7.56074 -0.780583 3 7.70184
-7.56059 1.24277 -0.781872 3 7.70184
-7.56112 -1.2396 -0.781804 3 7.70184
1.23971 -7.56127 -0.780172 3 7.70184
1.24292 7.5607 -0.780587 3 7.70184
7.56085 -1.24281 -0.779298 3 7.70184
7.56138 1.23956 -0.779366 3 7.70184
END
On Thu, 28 Aug 2008, ifeffit-request at millenia.cars.aps.anl.gov wrote:
> 1. Problem reproducing spectrum for Ti complex (Janine GRATTAGE)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Thu, 28 Aug 2008 10:42:31 +0200
> From: Janine GRATTAGE <janine.grattage at esrf.fr>
> Subject: [Ifeffit] Problem reproducing spectrum for Ti complex
> To: Ifeffit at millenia.cars.aps.anl.gov
> Message-ID: <48B664F7.6010704 at esrf.fr>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Dear IFEFFIT mailing list,
>
> I have been trying to reproduce the XANES spectrum of a titanium
> compound (titanium phthalocyanine dichloride) using FEFF 8.4. The
> overall shape is reproduced reasonably well, but I wanted to ask the
> mailing list users if they have any ideas as to how to improve the
> details such as the pre-edge (to give two distinct peaks) and peak
> positions over the absorption edge.
>
> I have attached a file showing the experimental spectrum, two FEFF input
> files and the corresponding XMU output files. These two files have the
> same atomic co-ordinates for the molecule, but one has 'standard'
> broadening and the Fermi level has been shifted by -1eV (geom1) where
> the other has reduced experimental broadening (-3) a shifted Fermi
> level, and smaller step size (geom1acc).
>
> I have tried changing the geometry of the molecule by moving one or both
> of the Cl atoms, and by trying a flat molecular geometry rather than the
> 'umbrella' shape in the attached files, but the spectra attached are the
> best match to experiment. Any help or suggestions on improvements would
> be greatly appreciated.
>
> Best regards and thanks in advance,
>
> Janine Grattage
>
> --
> Dr Janine GRATTAGE
> Postdoctoral Fellow, ID26
> European Synchrotron Radiation Facility (ESRF)
> Sector 26, BP 220
> 6, rue Jules Horowitz,
> 38043 Grenoble, Cedex 9, FRANCE
> Tel: +33(0)4 38 88 19 30
> Email: janine.grattage at esrf.fr
>
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