Scattering length for fermionic alkali atoms

We examine the use of the WKB approximation to determine the p-wave scatteringlength. For this we solve the p partial wave Schrödingerequation and analyse the validity of adopting the semiclassical solution toevaluate the constant factors in the solution. We also calculate the p-wavescattering lengths of ⁶Li and ⁴⁰K for the a³Σ⁺ _u andX¹Σ⁺ _g states respectively using the variable phase method. Thep-wave scattering lengths of ¹³²Cs and ¹³⁴Cs are also calculated.Based on our calculations, the value of the p-wave scattering lengths of⁶Li and ⁴⁰K are -36a_o and -95a_o respectively.