(*Electronic correlation and "anticorrelation" in the helium atom, described in Fig.10.2*)
b=(E^(-1))
a0=(E^(-(Sqrt[(x^2)+(y^2)])))
HFA=a0*Exp[-Sqrt[1^2]]
Plot3D[HFA,{x,-2.,2.},{y,-2.,2.},PlotPoints->41]
HFB=a0*Exp[-Sqrt[(-1)^2]]
Plot3D[HFB,{x,-2.,2.},{y,-2.,2.},PlotPoints->41]
c0=(E^(-((x^2)+(y^2))))
c1=(E^(-((((x-1))^2)+(y^2))))
CGA=c0 (E^(-2 ((x^2)+(y^2))))
CGB=c0 (E^(-2 ((((x-1))^2)+(y^2))))
PCGA=c0-CGA
PCGB= c0 (1-(E^(-2 ((((x-1))^2)+(y^2)))))
CZ1A=c0 (1+(1/2) (Sqrt[(x^2)+(y^2)]))
CZ1B=c0 (1+(1/2) (Sqrt[(((x-1))^2)+(y^2)]))
CZ2A=c0 (1+25 (Sqrt[(x^2)+(y^2)]))
CZ2B=c0 (1+25 (Sqrt[(((x-1))^2)+(y^2)]))
Plot3D[CGA,{x,-2.,2.},{y,-2.,2.},PlotPoints->41]
Plot3D[CGB,{x,-2.,2.},{y,-2.,2.},PlotPoints->41]
Plot3D[PCGA,{x,-2.,2.},{y,-2.,2.},PlotPoints->41]
Plot3D[PCGB,{x,-2.,2.},{y,-2.,2.},PlotPoints->41]
Plot3D[CZ1A,{x,-2.,2.},{y,-2.,2.},PlotPoints->41]
Plot3D[CZ1B,{x,-2.,2.},{y,-2.,2.},PlotPoints->41]
Plot3D[CZ2A,{x,-2.,2.},{y,-2.,2.},PlotPoints->41]
Plot3D[CZ2B,{x,-2.,2.},{y,-2.,2.},PlotPoints->41]