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6.4 Atomic orbitals                       179
                                                                   5=2
                                                         1      Z
                        j2p x i  2 ÿ1=2 (j2p 1 i‡j2p ÿ1 i) ˆ          re ÿ Zr=2a 0  sin è cos j (6:61a)
                                                      4(2ð) 1=2  a 0
                                                                      5=2
                                                            1     Z
                        j2p y i ÿi2 ÿ1=2 (j2p 1 iÿj2p ÿ1 i) ˆ           re ÿ Zr=2a 0  sin è sin j
                                                        4(2ð) 1=2  a 0
                                                                                         (6:61b)

                        where equations (A.32) and (A.33) have been used. These new orbitals j2p x i
                        and j2p y i are orthogonal to each other and to all the other eigenfunctions
                        jnlmi. The factor 2 ÿ1=2  ensures that they are normalized as well. Although
                        these new orbitals are simultaneous eigenfunctions of the Hamiltonian operator
                                                                                      ^
                        ^
                                            ^ 2
                        H and of the operator L , they are not eigenfunctions of the operator L z .
                          If we now substitute equations (5.29a), (5.29b), and (5.29c) into (6.61a),
                        (6.61b), and (6.60a), respectively, we obtain for the set of three real 2p orbitals
                                                                5=2
                                                      1      Z
                                            j2p x iˆ               xe ÿ Zr=2a 0          (6:62a)
                                                   4(2ð) 1=2  a 0
                                                                5=2
                                                      1      Z
                                           j2p y iˆ                ye  ÿ Zr=2a 0         (6:62b)
                                                   4(2ð) 1=2  a 0
                                                              5=2
                                                    1     Z
                                            j2p z iˆ            ze ÿ Zr=2a 0             (6:62c)
                                                   ð 1=2  2a 0
                        The subscript x, y,or z on a 2p orbital indicates that the angular part of the
                        orbital has its maximum value along that axis. Graphs of the square of the
                        angular part of these three functions are presented in Figure 6.2. The mathema-
                        tical expressions for the real 2p and 3p atomic orbitals are given in Table 6.2.




                        d orbitals
                        The ®ve wave functions for n ˆ 3, l ˆ 2 are
                                                         7=2
                                               1     Z      2 ÿ( Zr=3a 0 )  2
                             j3d 0 iˆj320iˆ   p      r e       (3 cos è ÿ 1)       (6:63a)
                                            81 6ð a 0
                                                          7=2
                                                 1     Z      2 ÿ( Zr=3a 0 )       ij
                            j3d  1 iˆj32   1iˆ   p        r e       sin è cos è e     (6:63b)
                                               81 ð a 0
                                                           7=2
                                                  1     Z      2 ÿ( Zr=3a 0 )  2   i2j
                            j3d  2 iˆj32   2iˆ    p        r e       sin è e          (6:63c)
                                               162 ð a 0
                          The orbital j3d 0 i is real. Substitution of equation (5.29c) into (6.63a) and a
                        change in notation for the subscript give
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