2.光的波粒二象性(1)

0.05 300
4.4 10
35
(m) 即4.410-24Å
B
K
发射电 子阴级
加 速 电 极

1 2
m0V
2
eU
m0
V
V
2eU m0
e U

or
h P

h m0V

De Broglie wavelength follows from 12.3 h A 2em0U U

h m0V 6.63 10
34
Exp 2. What wavelength is predicted by De Broglie wave for a beam of electrons whose kinetic energy is eU and velocity is v ? （VC） B From the law of m0 V conservation of energy, K 1 2 e 发射电 m0V eU U 2 加速电极 子阴级

h m0V 6.63 10
34
0.05 300
4.4 10
35
(m) = 4.410-24(Å)
Example 1. What wavelength is predicted by De Broglie wave for a bullet whose mass is m0=0.05kg and velocity is v=300m/s? Solve, ∵V << C
M Ni单晶
2) G.P. Thomson electron diffraction test
1927 年汤姆逊（G· Thomson）以600伏慢电子 P· (=0.5Å)射向铝箔，也得到了像X射线衍射一样的衍 射，再次发现了电子的波动性。 1937年戴维逊与GP汤姆逊共获当年诺贝尔奖. G· Thomson为电子发现人J· Thmson的儿子. P· J· 尔后人们又发现了质子、中子的衍射.
10

12.3 U
10
( m) or 12.3 U
12.3 U
Å
When U=100(V),

12.3 (Å)
Demonstration of De Broglie wave 1) C. J. Davisson and L. H. Germer Test 戴维逊--革末实验 Figure shows the apparatus of Davisson and Germer 实验装置：
X
E
wave
u
Z
particle which connects the wavelength of a light wave with the momentum of the associated photons.
De Broglie wave
Y H
De Broglie predicted that the wavelength of matter waves would also be given by λ= h / P where P would now be the momentum of the particle of matter.
加 速 电 极
B K
发射电 子阴级I源自M Ni单晶U
电 流 计
G
1）C. J. Davisson and L. H. Germer Test 实验装置： 加 B 速 K
发射电 子阴级
I
电 流 计
电 极


M Ni单晶 φ =50° I
G
U
Ni单晶
a d
a=0.215nm d=0.0908nm U=54(v)
De Broglie wave
Example 1. What wavelength is predicted by De Broglie wave for a bullet whose mass is m0=0.05kg and velocity is v=300m/s? Solve, ∵V << C
3) Electron double-slit diffraction test 电子双缝实验 1961年琼森（Claus Jö nsson）将一束电子加速 到50Kev，让其通过一缝宽为a=0.510-6m，间隔 为d=2.010-6m的双缝,当电子撞击荧光屏时,发现 了类似于光的双缝衍射的图样.
（De Brö glie wave .Wave-Particle Dualism ） The dual nature of light, particle and wave 光的波粒二象性 （frequency） h （momentum）P （wavelength） These two natures are connected by h. E h (1) 2 2 2 E E0 ( P c) h h P E / C (2) C （energy） particle E wave
4.德布罗意波、波粒二象性

De Broglie assumed that the wavelength of predicted matter waves was given by the same relationship that held for light namely, or λ= h / P
U
实验装置： B K
发射电 子阴级
加 速 电 极
I


suppose electrons G 电 are waves.
流 计
U De Broglie wavelength of electron waves would be Experigiven by h 12.3 A (9)mental value 2em0U U is given by 2 3. From Bragg’s law 2d sin k k 1 φ=50o . h This is 2d sin k (10) excellent 2em0U agreement. o φ=51
大量电子一次性 行为
电子双缝实验 — 一个电子多次重复性行为
Scanning tunnelling microscope 扫描隧道显微镜
扫描隧道显微镜中的原子形象
中文书：19—15, 19—16, 外文书：48—1.