0.5 1.0 1.5 2.0 - 1 0 1 2 3 4 5 6 ✠ ✡ 1 2 3 4 - 4 - 2 0 2 4 6 8 10 38 FIG. 22: The normalized first excited 2 p 1 2 wave functions ψ$_{a}$ ( x ) and - ψ$_{b}$ ( x ) for the case when V$_{s}$ ( x ) and V$_{v}$ ( x ) have equal asymptotic slopes. Compare this solution for the massless quark case ( u and d quarks) shown in Fig. 6. Compare also with the 2 p 1 2 hydrogen-atom wave functions, ψ$_{a,b}$ ( x ) in Figs. 13 and 14 (dashed curves). FIG. 21: The normalized first excited 2 s wave functions ψ$_{a}$ ( x ) and − ψ$_{b}$ ( x ) for the case when V$_{s}$ ( x ) and V$_{v}$ ( x ) have equal asymptotic slopes. Compare this solution for the massless quark case ( u and d quarks) shown in Fig. 4. Compare also with the 2 s hydrogen-atom wave functions, ψ$_{a,b}$ ( x ) in Figs. 11 and 12 (dashed curves), noting that the smeared Coulomb attraction in V$_{v}$ now forces ψ$_{b}$ (0) to be 0 instead of a finite value.