MSRFIT and Related Utilities at TRIUMF
Originally written by Andi Kratzer,
Susanne J. Flaschin and others at T.U. München.
The original files can be viewed on their Web site at
www1.physik.tu-muenchen.de/~kratzer/fit/fit.html.
We are grateful to that group for undertaking the initial effort,
and we hope they will approve of any updates and additions we make
here at TRIUMF.
Originally a text message from David Noakes, now corrected, improved and
pretty-printed in html. Contains an abbreviated but excellent overview
of the input-file format, follwed by several example input files.
for fitting tabulated functions
Static Relaxation Functions
Static Zero Field (ZF) Relaxation Functions
Some static functions must be tabulated because
there is no analytical version in closed form.
-
caf2_zf_nnn.tbl:
This is (I think) the static relaxation function for a muon in
the FµF site in CaF2 in zero magnetic field,
including next-nearest neighbour dipolar interactions.
Generated by Moreno Celio around 1985-6.
Static Longitudinal Field (LF) Relaxation Functions
Similarly, although one can write integral equations for various LF
functions, there is no closed-form analytical expression available
for economical fitting, so we make tables.
-
glf.tbl:
Static Gaussian LF relaxation function.
-
llf.tbl:
Static Lorentzian LF relaxation function.
-
cu_100_lf.tbl:
Static relaxation function for a muon in the octahedral site
in pure crystalline copper metal with a LF
(and the initial muon polarization)
along the <100> direction.
Generated by Moreno Celio around 1985-6.
-
cu_110_lf.tbl:
Same thing except along the <110> direction.
-
cu_111_lf.tbl:
Same thing except along the <111> direction.
Dynamic Relaxation Functions
Dynamic Zero Field (ZF) Relaxation Functions
-
gauss.tbl:
Dynamic Gaussian ZF Kubo-Toyabe (KT) relaxation function,
the prototype of all these tabulated functions,
generated by me (Jess Brewer) in the early 1980's
using brute force Monte Carlo methods.
An earlier version was created by Tomo Uemura,
using more sophisticated methods; I just wanted to make sure
a dumb version using classical dynamics worked the same.
-
kdgzf.tbl:
Same thing, but generated from the static Gaussian ZF
KT function using Kehr's dynamicization method.
-
kdlzf.tbl:
Same as above except for a Lorentzian field distribution.
-
td_caf2_zf.tbl:
Dynamic relaxation function for a muon in the FµF site
in CaF2 in ZF, dynamicized by the Turner method.
-
td_naf_zf.tbl:
Dynamic relaxation function for a muon in the FµF site
in NaF in ZF, dynamicized by the Turner method
(invented by Eric Turner in the early 1980's, I think).
Dynamic Longitudinal Field (LF) Relaxation Functions
Beware of trying to fit outside the tabulated limits.
-
kdglf.tbl:
Generated from the static Gaussian LF KT function
using Kehr's dynamicization method.
-
kdllf.tbl:
Same as above except for a Lorentzian field distribution.
-
td_cu_100_lf.tbl:
Dynamic relaxation function for a muon in the octahedral site
in pure crystalline copper metal with a LF
(and the initial muon polarization)
along the <100> direction.
Dynamicized by the Turner method.
-
td_cu_110_lf.tbl:
Same thing except along the <110> direction.
-
td_cu_111_lf.tbl:
Same thing except along the <111> direction.
Other Relaxation Functions
Too numerous to list here. Many are tabulated in the form of so-called
"OMNI Tables" (a more generalized format than the above, which are
so esoteric I can't remember their structure myself!) and others are being
invented all the time. See the "Relaxation Functions" Forum on the
ISMS Bulletin Board for more details.
Jess H. Brewer
Last modified: Sat Dec 14 20:35:12 PST 2002