function kl = kfunc(x,eigw);
% y''(r) + kfunc(r) * y(r) =0
% Tesfunktion mit kfunc(r) = E - V(r)
% V .. Prokofjew potential


if x < 0.01
    q = 11 * x;
elseif x < 0.15
    q = - 26.4 * x^2 + 11.53 * x - 0.00264;
elseif x < 1
    q = -2.84 * x^2 + 4.46 * x + 0.5275;
elseif x < 1.55
    q = 1.508 * x^2 -4.236 * x + 4.876;
elseif x < 3.3
    q = 0.1196 * x^2 + 0.2072 * x + 1.319;
elseif x < 6.74
    q = 0.0005 * x^2 + 0.9933 *x + 0.0222;
else
    q = x;
end

v = - 2/(x^2) * q;

kl = eigw - v;

