252 
IONISATION, DIFFUSION, ROTATION 
This is an example of conditions giving a rather clean ionisation since 
the ionisations in progress are mostly confined to a narrow range of energy 
A = 1-2 to 1*9 A. The removal of electrons from deeper energy levels has 
scarcely begun and removal from higher levels is nearly complete. Only 
those electrons, if any, at an energy level within these limits require 
detailed consideration. How this affects the atoms of different elements 
will be seen from Table 30. For titanium (Z = 22) the last K electron is 
detached at A = T9, so that for titanium and lighter elements the final 
ionisation is very far advanced and the ions are mostly bare nuclei. After 
titanium there will be a short sequence of elements in critical condition 
as regards K ionisation and retaining mostly 1 or 2 A electrons; the sequence 
ends at zinc (Z = 30) for which the first K ionisation requires T3 A so that 
x is not much more than fa. Then follows a much longer sequence 
Z = 31-45 for which the range A = 1-2-1-9 falls in the gap between 
the K and L ionisations; these will be practically all helium-like ions 
retaining two K but no L electrons. For rhodium (Z = 45) the last L 
ionisation is fa complete. Elements from 45 to 73 are in various stages of 
L ionisation; for tantalum (Z = 73) the first L ionisation is only t l com 
plete. Here we reach the gap between L and M ionisation and the ions 
are neon-like retaining 10 electrons. The heaviest elements may retain 
two or three M electrons*. 
Table 30. 
Energy Levels. Wave-lengths in Angstroms. 
z 
Elem. 
K 
K' 
L' 
M 1 
M' 
A T i 
Z + l, 2, 
3 
13 
A1 
7-95 
5-39 
175 
30 
Si 
P 
S 
17 
Cl 
4-38 
3-15 
62-0 
16-2 
— 
— 
— 
A 
K 
Ca 
21 
Sc 
2-75 
2-07 
30-4 
10-1 
— 
— 
— 
Ti 
V 
Cr 
25 
Mn 
1-89 
1-46 
19-05 
6-89 
— 
— 
— 
Fe 
Co 
Ni 
29 
Cu 
1-38 
1-08 
13-05 
5-00 
— 
— 
— 
Zn 
Ga 
Ge 
33 
As 
1-04 
•84 
— 
3-79 
— 
— 
— 
Se 
Br 
Kr 
37 
Rb 
•814 
•666 
— 
2-97 
— 
— 
— 
Sr 
Y 
Zr 
41 
Nb 
•650 
•542 
5-22 
2-40 
611 
8-5 
— 
Mo 
— 
Ru 
45 
Rh 
•533 
•450 
4-13 
1-97 
41-0 
— 
— 
Pd 
Ag 
Cd 
49 
In 
•443 
— 
3-30 
1-65 
— 
— 
— 
Sn 
Sb 
Te 
53 
I 
•373 
— 
2-71 
1-40 
21-5 
4-44 
— 
X 
Cs 
Ba 
57 
La 
•319 
— 
2-25 
1-20 
14-8 
3-71 
— 
Ce 
Pr 
Nd 
61 
— 
•274 
— 
1-91 
1-04 
11-9 
3-15 
— 
Sm 
Eu 
Gd 
65 
Tb 
•238 
— 
1-64 
•92 
9-96 
2-71 
— 
Ds 
Ho 
Er 
69 
Tm 
•208 
— 
1-43 
— 
8-40 
2-35 
— 
Yb 
Lu 
Hf 
73 
Ta 
•184 
— 
1-25 
— 
7-14 
2-07 
415 
W 
— 
Os 
77 
Ir 
•163 
— 
110 
— 
6-08 
1-83 
— 
Pt 
Au 
Hg 
81 
T1 
•143 
— 
•98 
— 
5-16 
1-63 
95 
Pb 
— 
83 
Bi 
•136 
— 
•92 
— 
4-76 
1-54 
70-0 
Po 
— 
Nt 
92 
U 
•107 
•107 
•72 
•45 
3-49 
1-22 
330 
— 
— 
— 
* These conclusions being based on a first approximation are subject to revision.