dear all users
I am interested in calculating velocity autocorrelation function
of graphene in In contact with water.
I have used lammps-30Jan14 and compute vacf command to obtain VACF of graphene plate in my system. “Fix Ave/time” has been used to output the data. the results from VACF are incorrect, in such a way that the VACF values continuously fluctuate around zero .I do not know what is the problem?
my input script:
fix 1 G spring/self 50.0 xy
fix 4 water shake 0.0001 10 0 m 15.999400 b 3 a 6 #m 15.999400
fix 5 all npt temp 230.0 230.0 100.0 x 1.0 1.0 1000.0 y 1.0 1.0 1000.0
velocity all create 230.0 35281345 rot yes dist gaussian
compute 1 G vacf
fix ct G ave/time 10 1000 10000 c_vac[1] c_vac[2] c_vac[3] c_vac[4] file vacf.txt
variable VACF equal c_vac[4]
fix VAC1 Gl print 100 “${VACF}” file vacprint.txt screen no
thermo 500
the figure attached for VACF data
