2.4 Effect of Temperature on the Work Function
25
Table 2.5
Calculated temperature coefficient of work function with change in lattice parameter owing to vibration taken into account
Metal (structure) Plane Temperature coefficient of the work function
Temperature range (K)
α u
α hkl (r
c
= C)
α hkl
α hkl
vib
α u
+ α hkl
vib
Exp
Li (bcc)
(110)
−1.03
−0.33
0.78
−2.60
−3.63
100
≤ T
≤ 500
(100)
0.93
0.22
−6.77
−7.80
(111)
0.70
−0.10
−7.16
−8.19
Na (bcc)
(110)
−1.37
2.04
1.07
−7.93
−9.30
100
≤ T
≤ 500
(100)
1.91
0.51
−10.88 −12.25
(111)
1.38
−0.04
−11.52 −12.89
Al (fcc)
(111)
−0.23
−0.62
−0.10
1.88
1.65
100
≤ T
≤ 900
(100)
−0.69
−0.38
0.42
0.19
100
≤ T
≤ 500
−0.23
−0.46
500
≤ T
≤ 900
(110)
1.33
0.86
−3.44
3.67
100
≤ T
≤ 900
Pb (fcc)
(111)
−0.37
−1.38
−0.77
2.32
1.95
9.23 (poly)
100
≤ T
≤ 600
(100)
−1.41
−0.90
1.16
0.79
100
≤ T
≤ 200
−2.02
−2.39
200
≤ T
≤ 600
(110)
2.54
1.78
−10.90 −11.27
100
≤ T
≤ 600
Cu (fcc)
(111)
−0.27
−0.63
−0.15
−0.46
−0.73
−(1.16 ± 0.7)
100
≤ T
≤ 700
0.33
0.06
700
≤ T
≤ 1300
(100)
0.07
0.04
−1.51
−1.78
100
≤ T
≤ 1300
(110)
0.23
0.05
−2.09
−2.36
−(2.32 ± 1.16)
100
≤ T
≤ 1300
Ag (fcc)
(111)
−0.33
−0.04
−0.002 −1.45
−1.78
−2.36
100
≤ T
≤ 1100
(100)
0.25
0.09
−2.12
−2.45
(continued)