bei48482_FM

Molecules 273

b r



b

(b)

+

(a)

r

a



a

Contours of

electron probability

+

(c)

b r



a

A

R

+ +

b r



(d)

a

A

R

+ +

(e)

r

R = 0



He+(2p)

2+

Figure 8.6 (a)–(d) The combination of two hydrogen-atom 1swave functions to form the antisymmetric

H 2  wave function A. A stable H 2 molecular ion is not formed because now the electron has a smaller

probability of being between the protons than outside them. (e) If the protons could join together,

the resulting wave function would be the same as the 2pwave function of a Heion. In the 2pstate

a Heion has more energy than in the 2sstate.

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