﻿298 
  Dr. 
  L. 
  Vegard 
  on 
  the 
  X-Ray 
  Spectra 
  

  

  Further, 
  he 
  has 
  been 
  able 
  to 
  show 
  that 
  a 
  number 
  o£ 
  lines 
  

   in 
  the 
  X-ray 
  spectra 
  appear 
  as 
  doublets. 
  Thus 
  he 
  can 
  show- 
  

   that 
  K 
  a 
  and 
  K/ 
  form 
  a 
  doublet, 
  and 
  the 
  difference 
  of 
  

   frequency 
  can 
  be 
  calculated 
  from 
  his 
  theoretical 
  formula. 
  

  

  The 
  L-series 
  consists 
  of 
  at 
  least 
  13 
  lines. 
  It 
  is 
  of 
  

   importance 
  to 
  adopt 
  definite 
  names 
  for 
  these 
  lines. 
  

  

  Arranging 
  them 
  in 
  the 
  order 
  of 
  increasing 
  frequency, 
  

   Siegbahn 
  * 
  and 
  Sommerfeld 
  f 
  have 
  the 
  following 
  somewhat 
  

   different 
  denotation 
  : 
  — 
  

  

  Siegbahn 
  ^2 
  ^A 
  AAA 
  £57 
  ^2 
  73 
  7* 
  

  

  Sommerfeld 
  ea! 
  a 
  rj 
  v 
  /3 
  y 
  <j> 
  f 
  £ 
  ^ 
  % 
  ^ 
  

  

  Sommerfeld 
  finds 
  the 
  following 
  doublets 
  : 
  

  

  (*'£) 
  or 
  perhaps 
  («£), 
  (yo), 
  (e*), 
  and 
  (f&). 
  

  

  All 
  four 
  doublets 
  give 
  nearty 
  the 
  same 
  value 
  for 
  the 
  dif- 
  

   ference 
  of 
  frequency 
  of 
  its 
  two 
  components, 
  thus 
  : 
  

  

  £— 
  a'=8— 
  7=17— 
  e=&— 
  ?. 
  

  

  Recently 
  Debye 
  f 
  has 
  attacked 
  the 
  problem 
  in 
  a 
  some- 
  

   what 
  different 
  way. 
  His 
  method 
  may 
  be 
  considered 
  as 
  an 
  

   application 
  of 
  Bohr's 
  frequency 
  law 
  to 
  systems 
  consisting 
  

   of 
  more 
  than 
  one 
  electron. 
  

  

  Assuming 
  that 
  all 
  atoms 
  which 
  give 
  the 
  K-radiation 
  have 
  a 
  

   ring 
  next 
  to 
  the 
  nucleus 
  of 
  p 
  electrons, 
  he 
  is 
  able 
  to 
  deduce 
  

   a 
  theoretical 
  formula 
  for 
  the 
  K-line 
  by 
  putting^ 
  = 
  3. 
  

  

  His 
  deduction 
  is 
  based 
  on 
  the 
  following 
  assumptions 
  : 
  — 
  

  

  (a) 
  The 
  angular 
  momentum 
  of 
  each 
  electron 
  in 
  the 
  normal 
  

   ring 
  is 
  that 
  supposed 
  by 
  Bohr 
  for 
  the 
  normal 
  state 
  of 
  the 
  

   atom 
  (equation 
  1). 
  

  

  (b) 
  When 
  an 
  electron 
  is 
  removed 
  from 
  the 
  ring 
  the 
  

   angular 
  momentum 
  of 
  the 
  remaining 
  electrons 
  is 
  supposed 
  

   to 
  be 
  preserved. 
  

  

  (c) 
  A 
  line 
  belonging 
  to 
  the 
  K-series 
  is 
  supposed 
  to 
  be 
  

   formed 
  when 
  an 
  electron 
  recombines 
  to 
  the 
  broken 
  ring 
  

   from 
  a 
  secondary 
  stability 
  state 
  (circle) 
  corresponding 
  to 
  

  

  an 
  angular 
  momentum 
  r 
  -~- 
  where 
  t 
  is 
  a 
  whole 
  number 
  

   greater 
  than 
  1. 
  

  

  (d) 
  When 
  an 
  electron 
  recombines 
  in 
  one 
  step 
  from 
  a 
  

  

  * 
  M. 
  Siegbahn, 
  a 
  Bericlit 
  iiber 
  die 
  Rontgenspektren 
  der 
  chemischen 
  

   Eleniente," 
  Jahrbuch 
  d. 
  Radioakt. 
  u. 
  Elektronik, 
  xiii. 
  p. 
  296 
  (1916). 
  

   t 
  Loc. 
  cit. 
  p. 
  133. 
  

   % 
  P. 
  Debye, 
  Phys. 
  Z.S. 
  xviii. 
  p. 
  276 
  (1917). 
  

  

  