A[x_]=(1/x)-(1+(1/x))Exp[-2 x];
B[x_]=(1+x)Exp[-x];
S[x_]=(1+x+((x^2)/3))Exp[-x];
H11[x_]=13.6(((2/x)-1)-2 A[x]);
H12[x_]=13.6(((2/x)-1)S[x]-2 B[x]);
Emas[x_]=((H11[x]+H12[x])/(1+S[x]));
Emenos[x_]=((H11[x]-H12[x])/(1-S[x]));
Plot[{Emas[x],Emenos[x]},{x,1,3}]

Plot[B[x],{x,0,10},PlotRange->{0,All}]

Plot[{Emas[x]},{x,1,4}]

Plot[{Emenos[x]},{x,1,40}]

ψs[r_,θ_]=(1/(Sqrt[π]))Exp[-r];
r2[x_,r_,θ_]=(Sqrt[(r^2)+(x^2)-2x r Cos[θ]]);
Cmas[x_]=(Emas[x]-H11[x])/(H12[x]-Emas[x]S[x]);
Cmenos[x_]=(Emenos[x]-H11[x])/(H12[x]-Emenos[x]S[x]);
λ1mas[x_]=1/(Sqrt[1+((Cmas[x])^2)+2 Cmas[x] S[x]]);
λ2mas[x_]=Cmas[x]/(Sqrt[1+((Cmas[x])^2)+2 Cmas[x] S[x]]);
λ1menos[x_]=1/(Sqrt[1+((Cmenos[x])^2)+2 Cmenos[x] S[x]]);
λ2menos[x_]=Cmenos[x]/(Sqrt[1+((Cmenos[x])^2)+2 Cmenos[x] S[x]]);
ψmas[x_,r_,θ_]=λ1mas[x]ψs[r,θ]+λ2mas[x]ψs[r2[x,r,θ],θ];
ψmenos[x_,r_,θ_]=λ1menos[x]ψs[r,θ]+λ2menos[x]ψs[r2[x,r,θ],θ];

x=2.5`
Dx=2;
Lx=x+Dx;
Ly=2;
Emas[x]
Emenos[x]
asra=N[((2 Ly)/(2 Dx+Lx))];
angulo[z_,y_]=Switch[{z,y},
{Abs[z],Abs[y]},ArcTan[(y/z)],
{-Abs[z],Abs[y]},π-ArcTan[Abs[(y/z)]],
{-Abs[z],-Abs[y]},π+ArcTan[Abs[(y/z)]],
{Abs[z],-Abs[y]},2 π-ArcTan[Abs[(y/z)]]];
DensityPlot[((ψmas[x,(Sqrt[(z^2)+(y^2)]),angulo[z,y]])^2),{z,-Dx,Lx},{y,-Ly,Ly},PlotPoints->100,Mesh->False,AspectRatio->asra,FrameLabel->{"𝓍","𝓎"},PlotLabel->"(𝒶)",ImageSize->300,PlotRange->All]
Export["bondcerca.jpg",%,"JPEG"];
DensityPlot[((ψmenos[x,(Sqrt[(z^2)+(y^2)]),angulo[z,y]])^2),{z,-Dx,Lx},{y,-Ly,Ly},PlotPoints->100,Mesh->False,AspectRatio->asra,FrameLabel->{"𝓍","𝓎"},PlotLabel->"(𝒷)",ImageSize->300,PlotRange->All]
Export["antibondcerca.jpg",%,"JPEG"];

Plot[(((ψmenos[2.49,(Sqrt[(z^2)]),angulo[z,0]]))^2),{z,-Dx,Lx},PlotRange->All]

Plot[ψmas[2.49,(Sqrt[(z^2)]),angulo[z,0]],{z,-Dx,Lx},PlotRange->All]

Plot[Emas[x],{x,0,30}]

Emas[2.5]+13.6

FindMinimum[Emas[x],x]

FindMinimum[Emas[x],{x,2.5}]

Plot[{Emas[x]},{x,1,40},PlotRange->{All,-13.56}]