What is a "Goldman-Shen" experiment?

Gerald Pearson (gpearson@umaxc.weeg.uiowa.edu)
Fri, 15 Oct 93 17:50:25 -0500


Some time ago, we collected some solids deuterium (quad echo) spectra of some
polymer which had been soaked in D2O for various times. The samples were from
another department. We found 2 lines: a broad line, and a relatively sharp
one with a slightly different chemical shift. The broad line completely
overlapped the sharp one, so we extracted widths, areas, and positions with a
curve-fitting program. The broad & sharp peaks presumably arose from "bound"
and "free" water, respectively; pumping on the wet polymer pellets first
removes the sharp peak, and then (much more slowly) the broad peak.

Since than, the grad student left the University, a manuscript was written and
submitted, and a referee indicated that it would be nice to do a "Goldman-
Shen", or even better a "2D" experiment. (I think this was in connection with
the question of domain size or maybe exchange rate between sites.) The
authors of the manuscript have asked me to help, but I don't have the foggiest
idea what experiments the referee has in mind. Nor can I think of anything
that might fish out exchange rate or domain size information _in_ _this_
_situation_, with the possible exception of multi-quantum NMR. (i.e.,
measuring how high an order of multi-quantum coherence that it's possible to
excite in the sample, and therefore how many spins are in the largest
"domain".) This area is outside of my experience, because >99.9% of our work
is solutions NMR, and we pull our MSL-300 solids probes out of the cabinet
only about once or twice a year to do some CP/MAS or deuterium quad-echo.

CAN ANYONE OUT THERE HELP?
1. What's a "Goldman-Shen"? I'm not even absolutely positive that it's
an NMR experiment! A grad student did a computer literature search, but
didn't find anything useful.
2. What kind of 2D experiment(s) would give info on domain size and/or
(presumably _very_ slow) exchange rate _in_ _a_ _solid_, when the peaks
overlap so severely?

Any suggestions, comments, literature references, etc. would be greatly
appreciated.
--------------------------------------------------------------------
Gerald A. Pearson INTERNET: gpearson@umaxc.weeg.uiowa.edu
Chem. Dept., Univ. of Iowa VOICE: 319-335-1336
Iowa City, IA 52242-1219, USA FAX: 319-335-1270
--------------------------------------------------------------------