On 07/29/2015 06:01 PM, Ganesh Subramanian wrote:
1. *Using the FOLP card*: The actual cluster size is about 180 atoms
extending upto 18 A in radial distance from the central cobalt atom. But
there are quite a few instances of Hydrogen atoms that are too close. I
tried the FOLP with the recommendation for Hydrogen of 0.8, I seem to
get a syntax type error, that i cant figure out. I checked the crystal
structure and the smallest hydrogen bond distance is 0.89 A. (I have
attached the corresponding input and log file with suffix 'full cluster')
In Feff the "TWO ATOMS VERY CLOSE TOGETHER" message gets shouted at you
when you have atoms that are separated by 1.75 Angstroms or less. That
message has nothing to do with the FOLP setting.
2. *SCF for small cluster*: Since the problem with the hydrogen
distances persisted, I decided to run the calculation for a smaller
cluster (about 50 atoms). I used the conditions as prescribed for small
clusters - SCF 5.0 1, FMS 5.0 1, RPATH -1. Those hydrogens that were too
close (within this smaller cluster, there were about 3 of them, and none
in the first or second shell of co-ordination) were removed manually.
Now, I did not have the error on distances, did not require the FOLP
card to be manually altered, but the log1 file seems to suggest that the
SCF is not calculated. I cant figure why that is the case. (I have
attached the corresponding input and log file with suffix 'small cluster')
When I ran feff 8.40, I got same the contents of the log1.dat file, but
with these additional lines:
Core-valence separation
WARNING: fatal error in subroutine corval. Try
to reduce ca1 in SCF card. If does not help,
SEND bug report to AUTHORS
CORVAL-1
I don't quite know what that means, but it gives some hints. The source
code corval.f tells us that is "Finds the core-valence separation for
the cluster of atoms." I simply am not knowledgeable enough about the
details of Feff to know why your cluster triggered this warning.
B
--
Bruce Ravel ------------------------------------ bra...@bnl.gov
National Institute of Standards and Technology
Synchrotron Science Group at NSLS-II
Building 535A
Upton NY, 11973
Homepage: http://bruceravel.github.io/home/
Software: https://github.com/bruceravel
Demeter: http://bruceravel.github.io/demeter/
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