[gmx-users] regarding hydrogen bond correlation function for Cdd for TIP4P/2005 water model

[Abhinav Srivastava (P14CHM002)]

Dear Gromacs Users,

Kindly consider this as my query mail as in the last mail, subject line was
not complete. I apologize for the same .
I am trying to calculate hydrogen bond correlation function Cdd(t) for bulk
water (TIP4P/2005 water) using reversible geminate recombination as
mentioned in
Markovitch et al., J. Chem. Phys.,129,084505(2008).

Following is the command which I have used :

g_hbond -f NVT.xtc -s NVT.tpr -n bulk-water.ndx -b 0 -e 100 -P 1 -temp 308
-geminate dd -ac Cdd-bulk-water.xvg

I have simulated two systems viz. smaller system consisting of 851 water
molecules and a bigger system consisting of 1944 water molecules. I am not
able to get t^-3/2 scaling in hydrogen bond correlation function for Cdd
case in both these systems. It would be nice if you can please help me.
Thanks in advance.

-- 
*Abhinav Srivastava*
*Research Scholar*
Indian Institute of Technology, Jodhpur
Rajasthan