Dear James,
I believe the best way to go is to actually measure those corrections to
the Se atomic scattering factor (during your anomalous diffraction
experiment, you probably had a means to measure the fluorescence emitted
by your anomalous scatterer(s), during your energy scan, from where
f_prime can be directly deduced, and then f_dp; probably your actual raw
data have been kept and you can still do it now!)
The reason for this, is that the tabulated anomalous (imaginary) and
dispersive (real) corrections to f_0 for any given element, work well at
energies other than absorption edges; near the edge (where your
anomalous signal will be maximized, the point you probably want to to
collect at!), features affecting the actual chemistry of your Se atoms
(such as local environment, oxidation state, etc) will eventually lead
to significant modifications to the theoretical values (e.g. if
carefully chosen, at the so called 'peak' wavelength, when f_dp is max,
Se f_p ~(-)9-(-10) & f_dp~6-6.5)
HTH,
alejandro
james09 pruza escribió:
Dear All,
Please suggest the Peak wavelength of SeMet and the corresponding
f_prime and f_doubleprime.
In one of the journal I got it is 0.97905 A and Phenix manual shows
f_prime and f_doubleprime to be -3 and 4 respectively.
How can one deduce f_prime and f_doubleprime for any HA at a
particular wavelength.
Thanks.
James.
--
Alejandro Buschiazzo, PhD
Research Scientist
Laboratory of Protein Crystallography
Pasteur Institute of Montevideo
Mataojo 2020
Montevideo 11400
URUGUAY
Phone: +5982 5220910 int. 120
Fax: +5982 5224185
