[sdpd] Is it just awfully quiet these days?

["Roger Michael Sullivan" <smsulliv... @eos.ncsu.edu>]

Hi Everyone!

	In the interest of stimulating some discussion and seeking some help
let me lay out the problem I am working on.  I am a fourth year graduate
student and this is the first crystal structure I have ever tried to solve.
 The data was collected at NSLS beamline X7B under the guidance of Jon Hanson.
 A 0.7 mm capillary of CuAlCl4 was exposed to C2H4 and a new crystalline phase
formed.  Gravimetric analysis suggests an empircal formula of C4H8CuAlCl4 for
this gas adduct phase  The gas sorption was observed by time resolved powder
X-ray diffraction using a Translating Image Plate (TIP) detector built by P.
Norby.  An image plate of the full Debye-Scherrer rings for the ethylene copper
aluminum chloride adduct was analyzed using A. Hammersley's fit2d software.
 The fit2d parameters used on the unknown structure yielded d-spacings within
0.01 A for a control plate, CuGaCl4 (whose structure had been determined by
single crystal X-ray diffraction).  The output of the fit2d, in GSAS format
(von Dreele and Larson), was peak picked with GPLFST (acknowledgement?) and
then the CRYSFIRE (R. Shirley) interface to a suite of indexing software was
used.  Only TREOR (P. E. Werner) and ITO (acknowledgment?) yielded possible
unit cells (due to my not being familiar with the other routines, no doubt).
 Further discussion of my search for the correct unit cell (as well as an
edited peak list and screen formated gsas and instrumental data files of the
diffractogram) can be ftp'd from

chjmpc3.chem.ncsu.edu.
user:jobic
password:jobic

  At this point I am using the cells in C. Giacovazzo's EXTRA routine to
extract Fobs for hkl's.  I had trouble fitting the background in EXTRA so I did
a background subtraction using an EXCEL spread sheet and a curve fitting
program (CURVFIT).  I used the CONVERT (acknowledgment?)software convert ascii
files into Reit7 format for EXTRA.   Some trial runs with SIRPOW have not yet
produced any chemicaly reasonable value.
	I would like to try ESPOIR.  I have strong reasons to believe
tetrahedral tetrachloroaluminate anions are one of the consituents of the
structure and would like to enter them in as integral units, but do not know
how to proceed.
	I wish to acknowledge the collaboration of Haiming Liu of Clare Grey's
group at SUNY Stony Brook in this project.  Thank you all for your time in
reviewing my work and I would like to thank all the contributers to sdpd, as
well as the reitveld list, for discussions which have helped me get as far as I
have working on this solution.

Roger


Roger M. Sullivan
Department of Chemistry
Box 8204
North Carolina State University
Raleigh NC, 27965
smsulliv... @pams.ncsu.edu