The left (x < 0) and the right (x > 0) components of Ψ n (x) (n = 2,3) Ψ n (+) and Ψ n (-) (n = 2, 3) have clear parity labels, but other mathematical restrictions on the wavefunctions must now be considered. Ψ n (+) and Ψ n (-) (n > 1) clearly vanish at x = ±∞ and are finite at all the interior points. They are also continuous at all points including x = 0, and linearly independent. We may, however reject the even parity eigenfunctions (Ψ n (+) , n > 1) and accept only the odd parity eigenfunctions (Ψ n , n > 1) on the mathematical ground that the first derivative of Ψ n (-) (x) is continuous at x = 0 (the singular point) while the first derivative of Ψ n (+) (x) may not so be. This fact can be demonstrated in a slightly roundabout way. Let us consider the SE for the one-D H-atom for the quantum state Ψ n (-) (n > 1):