10.13 (a)
(b)
(c)
(d) The first two electrons will be in the (1,1) level, which is equal
to:
The two lowest-energy states are (n 1 ,n 2 ) equal to (1,1) and then
(1,2). The longest wavelength transition is from the (1,1) state to
the (1,2) and the change in energy is:
=7.9 × 10 −^20 J
10.14 (a)The wavefunction is zero for x≤− 2 a; x≥± 3 a; y≤−b; y≥± 2 b
(b)
(c)
10.15
−++
Z^22
2
2
2
2
2 mxxyz y xyz z^2
∂
∂
ψ
∂
∂
ψ
∂
∂
() (),, ψ() ()xyz,, E xyz,,,, (
⎛
⎝
⎜⎜
⎞
⎠
⎟⎟= ψ
ψ
π
(,) sin
()
xy
a
nx a
a
= ⎛x +
⎝
⎜⎜
⎞
⎠
⎟⎟
⎛
⎝
⎜
⎜
⎞
⎠
(^2) ⎟
5
2
5 ⎟⎟
⎛ +
⎝
⎜⎜
⎞
⎠
⎟⎟
⎛
⎝
⎜
⎜
⎞
⎠
⎟
⎟
2
33 b
ny y b
b
sin
π()
−+
⎛
⎝
⎜⎜
⎞
⎠
⎟⎟=
Z^22
2
2
2 mx xy y^2 xy E
∂
∂
ψ
∂
∂
() ψψ(),,(()xy,
λ
(. )( )
.
==
hc ××−−
ΔE
66 10 3 10
79
(^34) Js (^8) m s 1
××
− =×. −
10
20 25 10^6
J
m
ΔE
(. )
(. ) (
=
×
×
−
−−
66 10
891 10
1
10
34 2
31 9
Js
kg mm)^2..
2
(^22)
15
1
1
15
⎛
⎝
⎜⎜
⎞
⎠
⎟⎟ +
⎡
⎣
⎢
⎢
⎢
⎤
⎦
⎥
⎥
⎥
−
⎛
⎝
⎜⎜
⎞⎞
⎠
⎟⎟ +
⎡
⎣
⎢
⎢
⎢
⎤
⎦
⎥
⎥
⎥
⎧
⎨
⎪
⎩
⎪
⎫
⎬
⎪
⎭
⎪
2
12
E
h
m
n
L
n
g L
=
⎛
⎝
⎜⎜
⎞
⎠
⎟⎟ +
⎛
⎝
⎜⎜
⎞
⎠
⎟⎟
⎡
⎣
⎢
⎢
⎢
2
1
1
2
2
2
2
8
⎤⎤
⎦
⎥
⎥
⎥
=
⎛
⎝
⎜⎜
⎞
⎠
⎟⎟()+=
h
m
nn Exy
2 2
22
8
1
20
45
Å^00
=
×
××
−
−
(. )
(. )
663 10
8 9 11 10
1
10 1
34 2
31
Js
kg 00
1
(^10) 20 10
2
10
2
−−
⎛
⎝
⎜⎜
⎞
⎠
⎟⎟ +
×
⎛
⎝
⎜⎜
⎞
⎠
⎟⎟
⎡
⎣
⎢
⎢ mm
⎢⎢
⎤
⎦
⎥
⎥
⎥
E
h
m
n
L
n
L
=
⎛
⎝
⎜⎜
⎞
⎠
⎟⎟ +
⎛
⎝
⎜⎜
⎞
⎠
⎟⎟
⎡
⎣
⎢
⎢
⎢
2 ⎤
1
1
2
2
2
2
8
⎦⎦
⎥
⎥
⎥
ψ
π
() ()()xy X xY y sin
x
,
ÅÅ
==
⎛
⎝
⎜⎜
⎞
⎠
⎟⎟
⎛
⎝
⎜^2
⎜⎜ 10 10
⎞
⎠
⎟
⎟
⎛
⎝
⎜⎜
⎞
⎠
⎟⎟
⎛
⎝
⎜
⎜
⎞
⎠
⎟
⎟
2
20 ÅÅ 20
sin
πy
−+
⎛
⎝
⎜⎜
⎞
⎠
⎟⎟=
Z^22
2
2
2 mxxy y^2 xy E
∂
∂
ψ
∂
∂
() ψψ(),,(()xy,
ANSWERS TO PROBLEMS 461
9781405124362_5_end.qxd 4/29/08 9:17 Page 461