can somebody help ?

• To: mathgroup at smc.vnet.net
• Subject: [mg127331] can somebody help ?
• From: raj kumar <rajesh7796gm at gmail.com>
• Date: Tue, 17 Jul 2012 01:32:25 -0400 (EDT)
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```dear esteemed members of the forum,
hello from malaysia
i have this workable code for a scattering process called
HKrScattering.See below.Given a particular value of say l=1 and an
energy value of say En =2, and nsteps=1000,  the code gives the
correct result for the  phase shift.
however, i would like to generate a set of values for the phase shift
for different values of l, say for l=0 to l=5 for En=2.

I have tried using a do loop for this purpose but have not been able
to get correct results so far.

cheers
rk

j[l_, z_] := Sqrt[\[Pi]/2 z] BesselJ[l, z];
n[l_, z_] := Sqrt[\[Pi]/2 z] BesselY[l, z];

HKrScattering[l_, En_, nsteps_] :=
Module[{meV, \[Angstrom], \[Sigma], \[Mu], \[Lambda], k, s,
scat, \[Delta]},

meV =  1./(27.3 * 1000.);
en = En*meV;
\[Angstrom] =  1/0.52 ;
\[Sigma] = 3.57 \[Angstrom];
\[Epsilon] = 5.9 meV ;
V[r_] := \[Epsilon] ( (\[Sigma]/r)^12 - 2 (\[Sigma]/r)^6);
\[Mu] = (mH  mKr)/(mH + mKr) /. {mH -> 1836 , mKr -> 1836*136};
\[Lambda] = 2 \[Pi]/Sqrt[2 \[Mu] en] // N;
k = 2 \[Pi]/\[Lambda];
(*Print["\[Lambda]= ",\[Lambda]]*);
s = 5 \[Lambda]/nsteps;
x = {0.5 \[Sigma], 0.5 \[Sigma] + s};
\[Psi] = {0.0, 0.0001};
F[r_] := 2 \[Mu] ( V[r] + 1/(2 \[Mu] r^2) l (l + 1) - en);
Do[
\[Psi]m = \[Psi][[n - 1]];
\[Psi]n = \[Psi][[n]];
xm = x[[n - 1]];
xn = x[[n]];
xp = xn + s;
x = Append[x, xp];
Fn = F[xn];
Fp = F[xp];
Fm = F[
xm]; \[Psi]p  = (
2. \[Psi]n - \[Psi]m +
s^2/12. (10. Fn  \[Psi]n + Fm  \[Psi]m))/(1. - s^2/12. Fp);
\[Psi] = Append[\[Psi], \[Psi]p],
{n , 2, nsteps}
] ;
\[Psi] = \[Psi]/Max[\[Psi]];
scat = Transpose[{x, \[Psi]}];
nmax = Length[scat];
{r1, u1} = scat[[nmax]];
{r2, u2} = scat[[nmax - 1]];
K = (r1 u2)/(r2 u1);

j1 = j[l, k r1];
j2 = j[l, k r2];
n1 = n[l, k r1];
n2 = n[l, k r2];
\[Delta] =
ArcTan[ (K j1 - j2)/(K n1 - n2)];(*finding the phase shift*)
Print[\[Delta]]
(*Return[{scat,\[Delta]}*)]

```

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