Talk:Biaxial nematic

To me the matrix looks wrong. I'm not an expert...actually I'm just trying to figure things out. But after doing some calculations myself using other sources the diagonal elements of the matrix should be (source: Introduction to liquid crystals, Denis Andrienko, International Max Planck Research School, Modelling of soft matter, 11-15 September 2006, Bad Marienberg, September 14, 2006, http://www2.mpip-mainz.mpg.de/~andrienk/teaching/IMPRS/liquid_crystals.pdf):

0,0 element: 2/3 * S

1,1 element: -1/3 * S + T

2,2 element: -1/3 * S - T

Can anybody else confirm this? — Preceding unsigned comment added by 139.18.240.225 (talk) 15:06, 8 December 2015 (UTC)

What you say is standard in my textbooks too. The matrix in the article is of equivalent utility and I would guess it's the more popular version in some (experimental?) subfield of liquid crystal research we're not familiar with. But it looks like `their' S is defined with a factor of two more than `our' S, i.e. $S=\langle (3\cos \theta -1)\rangle$ vs $S=1/2\langle (3\cos \theta -1)\rangle$.

Note : of the 6 references, S and some matrix are defined only in the Bates and Luckhurst, and it's not exactly the one in the article either.CyreJ (talk) 15:13, 4 March 2022 (UTC)

I threw in a "citation needed" for now, does anyone have a reference that gives this form of the matrix? Maybe changing it soon.CyreJ (talk) 15:13, 4 March 2022 (UTC)