Hello
I am attempting to interpret a Platon TMA output, and need some advice
with a few points.
If anyone can help I'd be really grateful.
I have refined a structure with TLS parameters in GSAS and am running
it through Platon, as a trial, to make sure I understand the results.
I can reproduce results down to the following sections**, about which
I have 3 questions:
1) Are the T / L Tensors given w.r.t. the Cartesian system or the
Inertial System (or the crystal system)? The numbers are similar
(identical) to those refined by GSAS, so I guess Cartesian... is this
right?
2) What do the Eigenvectors/Values (EVs) of these tensors give? T & L
directions / magnitudes w.r.t. the basis used in 1?
3) The given EVs are stated to be w.r.t. the Inertial System, how are
they calculated?
I guess it will be something of the form eig(A U A') where A is a
transformation matrix (A' its transpose) and U is the tensor. However,
I have have tried various combinations based on the Inertial
coordinates, but I am obviously missing something.
Thanks in advance
Adam Calver
====================================================================================================================================
Inertial Tensor I, Eigenvectors and Eigenvalues of I in the Cartesian XO,YO,ZO
System and Angular Relation with X,Y,Z System
------------------------------------------------------------------------------------------------------------------------------------
XO YO ZO Value X Y
Z Origin (Mass-Weighted)
------------------------------------------------------------------------------------------------------------------------------------
I(1) -0.81405 0.58080 0.00000 99.34 144.49 24.49
90.00 X = 0.40040
I(2) -0.58080 -0.81405 0.00000 101.65 125.51 114.49
90.00 Y = 0.36758
I(3) 0.00000 0.00000 1.00000 101.92 90.00 90.00
0.00 Z = 0.25000
Librational Tensor, L(rad**2) Eigenvectors and
Eigenvalues of L in the Inertial System XI,YI,ZI
------------------------------------------------------------------------------------------------------------------------------------
XI YI
ZI rad**2 Deg**2 Deg
------------------------------------------------------------------------------------------------------------------------------------
0.00403( 0) -0.00001( 1) 0.00000( 1) L(1) -0.54686 0.83722
0.00000 0.00404 13.27 3.64
0.00404( 0) 0.00000( 0) L(2) 0.83722 0.54686
0.00000 0.00403 13.22 3.64
0.00157( 0) L(3) 0.00000 0.00000
-1.00000 0.00157 5.15 2.27
Translational Tensor, T(ang**2) Eigenvectors and
Eigenvalues of T in the Inertial System XI,YI,ZI
------------------------------------------------------------------------------------------------------------------------------------
XI YI
ZI Ang^2 Ang
------------------------------------------------------------------------------------------------------------------------------------
0.00436( 0) 0.00000( 0) 0.00000( 0) T(1) -0.62370 0.78167
0.00000 0.00436 0.06604
0.00436( 0) 0.00000( 0) T(2) 0.78167 0.62370
0.00000 0.00435 0.06598
0.00300( 0) T(3) 0.00000 0.00000
-1.00000 0.00300 0.05480
Cross Tensor, S(rad*Ang)
------------------------------------------------------------------------------------------------------------------------------------
0.00000( 0) 0.00000( 0) 0.00000( 0)
0.00000( 0) 0.00000( 0) 0.00006( 0)
0.00001( 0) -0.00002( 0) 0.00000( 0)
