TABLES
459
'
TABLE l.—SOME WORK
AND PHOTOELECTRIC THRESHOLDS
_
.
Photoelectric
Thermionic
»
Surface
,
'
(outgassed)
Threshold M,
Work function (pg,
Work
Angstroms
volts
'
volts
Ag
2610 (20° C.)
4.73
4.08 (925° C.)
2710 (600° C.)
4.56
Au
2650 (20° C.)
4.82
—
4.42 (1050° C.)
2610 (740° C.)
'
4.75
»
Cu
_
4.38
Fe
2620
4.72
'
Hg
2735
4.53
'
-
_
Mo
4.41
*
.
Ni
2463
5.01 -
'
.
Pd
2488
4.96
,
'
Pt
1962
6.30
_6—27 - "
Rh
2500
4.57
.
‘
4.58
274009)
4.50
_
.
‘
Sn
2820 (v)
.
4-38
'
2925 (liq.)
_
'
Ta
3050 (20° C.)
-,
4507 Ÿ
_
5150 (700° C.)
592
-
'
—.
.
.
_
Minimumïÿal‘ues
__
_
Th—W
4900
.
.
‘
2.52] =
262
“
_
l
BaO—Pt
9200
'.
'
”
.
Cs—Cs0.—Ag
:
…
'
_
.
i_—
®
'
''
Na—Pt
5900208
t:“
_,
K—Pt
.
77001Ê2
"
.' '
__
7950}38
* *
_
-
B “d“
_;