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lammps/examples/PACKAGES/phonon/2-1D-diatomic/plot.disp
2021-06-29 11:23:47 -04:00

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m = 1.
M = 2.
k = 1.
omp(x) = sqrt( k*(m+M)/(m*M)*(1. + (1.-4*m*M/(m+M)**2*(sin(pi*x))**2)**0.5))
omm(x) = sqrt( k*(m+M)/(m*M)*(1. - (1.-4*m*M/(m+M)**2*(sin(pi*x))**2)**0.5))
set xlabel 'q'
set ylabel '{/Symbol w}'
set xr [-0.5:0.5]
set yr [0:2.0]
set format y '%.1f'
set term post enha color 20
set out 'pdisp.eps'
set key top left
set xtics ("-{/Symbol p}/2a" -0.5, "{/Symbol G}" 0.0, "{/Symbol p}/2a" 0.5)
set samples 101
set grid xtics lt 9
plot omp(x) w l lt 1 lc 3 t 'Theory',\
omm(x) w l lt 1 lc 3 t '',\
'disp.dat' u 1:5 w p pt 7 ps 1.0 lt 1 t 'MD',\
'' u 1:6 w p pt 7 ps 1.0 lt 1 t ''