Chemistry Reference
In-Depth Information
Figure 2.17
The H
2
O molecule in the yz plane. 2
u
is the interbond (valence) angle
is immediately evident that symmetry AOs
23
of C
2v
symmetry are
(Magnasco, 2009a):
<
1
:
;
¼
p ð
þ
Þ
A
1
z
h
z
h
1
h
2
ð
2
:
176
Þ
:
1
B
2
:
y
;
h
y
¼
p ð
h
1
h
2
Þ
so that the normalized MOs
24
not interacting by symmetry are:
z
þl
h
z
1
y
þm
h
y
1
a
1
¼
p
;
b
2
¼
p
ð
2
:
177
Þ
2
þm
2
þl
,
m
and the orbital energies are found by
solving the secular equations:
l
The polarity parameters
H
zz
«
H
yy
«
H
yh
y
H
yh
y
H
h
y
hy
«
H
zh
z
H
zh
z
H
h
z
h
z
«
¼
0
¼
0
ð
2
:
178
Þ
Symmetry A
1
Symmetry B
2
The matrix elements in the H
€
uckel approximation are:
8
<
H
zz
¼ a
p
p
b
zh
H
h
z
h
z
¼ a
h
þb
hh
a
h
ð
2
:
179
Þ
H
zh
z
¼
:
23
The only AOs that can mix in the LCAO approximation.
24
Neglecting overlap for brevity.
