# Plot Eigenvalue Data

kmin = 0; (* min wave number *)
kmax = 5; (* max wave number *)
nopoints = 51;
step = (kmax - kmin)/(nopoints - 1);
ktable = Table[k, {k, kmin, kmax, step}];


I am trying to define a parameter that is easily changed. This parameter is the variable k, evaluated from 0 to 5 with 51 values in the range.

When I plot the eigenvalues of my problem using this parameter, I totally change my solutions when I change my parameter range (max-min) and/or steps. Can someone help me? My plot code is:

(* energy dispersion plot *)
xdisp = ListPlot[{sollower, solupper, wmenergytable,
fenergytable},
Joined -> True,
PlotStyle -> {Red, Black, {Dashed, Red}, {Dashed,
Black}},
PlotRange -> {{0, 5}, {0, 0.04}},
PlotLegends -> {"Lower Exciton", "Upper Exciton"},
AxesLabel -> {k, E}]

• Could you include all the code needed to show your problem? – Chris K Jan 20 '19 at 20:23
• hbar = 6.58212 10^-16; (* reduced planck constant *) restmass = 9.109383 10^-31; (* electron rest mass *) emass = 0.34* restmass; (* electron reduced mass *) hmass = 0.23* restmass; (* hole effective mass *) wmenergy0 = 15 10^-3; (* wannier exciton initial energy *) fenergy = wmenergy0 + 5 10^-3 ;(* frenkel exciton energy *) xmass = emass + hmass; \[Chi] = fenergy - wmenergy0; – David Facemyer Jan 20 '19 at 20:39
• xa[wmenergy_] := {{wmenergy, \[Chi]}, {\[Chi], fenergy}}; (* interaction matrix *) xe = {{xen, 0}, {0, xen}}; (* energy matrix *) xsol[k_] := NSolve[Det[xa[wmenergy] - xe] == 0, xen]; (* eigenenergies of the system *) wmenergy = wmenergy0 + (hbar^2 k^2)/(2*xmass); (* wannier exciton dispersion *) – David Facemyer Jan 20 '19 at 20:39
• wmenergytable = Table[wmenergy, {k, kmin, kmax, step}];(* table of wannier exciton energies *) fenergytable = Table[fenergy, {k, kmin, kmax, step}]; (* table of frenkel exciton energies *) xwmenergytable = Transpose[{ktable, wmenergytable, fenergytable}]; titles2 = {wavenumber, Ew, Ef}; xwmenergytable2 = Insert[xwmenergytable, titles2, 1]; – David Facemyer Jan 20 '19 at 20:40
• @DavidFacemyer please put that in the question body (using the edit button). It'll be much easier to find, copy, etc. there. – b3m2a1 Jan 20 '19 at 20:56