Interior angle of a triangle

[HarshaUmapathi]

Please refer the image.
How to figure out the angle α with only the following information
d_ClCr=R_Elmin+R_Einitr
The lines E_initC_r and E_initD are perpendicular.
R_Einitr and C_r are unknown and will be deduced with the help of α.
C_l, R_Elmin, ψ, d_ClEinit are known.