Two charges of $$-4 \mu$$C and $$+4 \mu$$C are placed at the points $$A(1, 0, 4)$$ m and $$B(2, -1, 5)$$ m located in an electric field $$\vec{E} = 0.20\hat{i}$$ V cm$$^{-1}$$. The magnitude of the torque acting on the dipole is $$8\sqrt{\alpha} \times 10^{-5}$$ N m, where $$\alpha$$ = _____.