This must be combined with a spin eigenfunction ↑↑, ↓↓, (↑↓+↓↑), or (↑↓−↓↑)...This must be combined with a spin eigenfunction ↑↑, ↓↓, (↑↓+↓↑), or (↑↓−↓↑), where the first arrow represents the spin state (ms=±1) of the first electron. ψ(r1,r2,s1,s2)=[u1100(r1)+u1100(r2)][u2100(r1)+u2100(r2)][↑↓−↓↑]