[gmx-users] Order parameter

[Hwankyu Lee]

Dear gromacs users,

I have used g_order and have some questions on results from g_order. In 
my monolayer system, the interface between water and lipids are normal 
to Z-axis, and lipids have CH2 tail regions. I wanted to know order 
parameter (Scc) of acyl chains of lipids.

1) I expected to see symmetry of Sx and Sy, but Sy and Sz are 
symmetrical, and Sx looks so different from Sy and Sz. could you 
explain why it happens?   Why Sy  and Sz are symmetrical and Sx looks 
so different?

2) I wanted to know order parameter of acyl chains of lipids in terms 
of Z-axis. I did like below.
g_order  -f ***.xtc  -n ***.ndx  -s ***.tpr  -o ***.xvg  -d z

And then, I read Z values for order parameter (Scc) of acyl chains of 
lipids. Is that right way?

Thanks for help in advance.

best,
Hwankyu.