# Homework Help: Calculate the scattering phase sift

1. Mar 7, 2009

### sanjibghosh

1. The problem statement, all variables and given/known data
calculate the scattering phase sift for given potential
v(r)=-a/r +b/r2( consider only s-wave scattering)
a=+ve constant
b=+ve constant

2. Relevant equations
phase sift=f(-k,0)/f(k,0)
k2=2mE/$$\hbar$$2
r*f(k,r)=solution of schrodinger equation
3. The attempt at a solution
I have solved the schrodinger equation and i have found that 'phase sift' =1
but physically i did not understand the ans..

2. Mar 8, 2009

### malawi_glenn

Re: scattering!!!

what does a positive phase shift tells you?

3. Mar 9, 2009

### sanjibghosh

Re: scattering!!!

i have found that
exp(2i$$\delta$$)=1
=>$$\delta$$=n*pi ,n=+ve or -ve integer
therefore s-wave contribution to the differential scattering cross section=lim(k2-->0)1/(k2 +k2cot2$$\delta$$)=0
i do not understand this.potential is nonzero but there is no scattering contribution!!