Irodov – Problems in General Physics

.17

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4

3

Diffuse

series

2

Principal series

3

Sharp

series

H

K-series

Fig. 6.8.

N

• Terms of alkali metal atoms:

T — (^) (n± CO 2 (6.3a)
where R is the Rydberg constant, a is the Rydberg correction.
Fig. 6.7 illustrates the diagram of a lithium atom terms.

• Angular momenta of an atom:
  ML = hjlL (L 1),^ (6.3b)
  with similar expressions for Ms and M 1.


• Hund rules:
  (1) For a certain electronic configuration, the terms of the largest S value
  are the lowest in energy, and among the terms of Smax that of the largest L
  usually lies lowest;

Li

Fig. 6.7.

(2) for the basic (normal) term J = IL — SI if the subshell is less than

half-filled, and J = L S in the remaining cases.

• Boltzmann's formula:
  Ns = g2
  e^ —(E,--E1)111T^ (6.3c)
  N I gi
  where g 1 and g 2 are the statistical weights (degeneracies) of the corresponding
  levels.


• Probabilities of atomic transitions per unit time between level 1 and a
  higher level 2 for the cases of spontaneous radiation, induced radiation, and
  absorption:
  PsP 21 - pind 21 p , pabs 12 = BAUM,
  where A21, B 21 , B12 are Einstein coefficients, uo, is the spectral density of radia-
  tion corresponding to frequency co of transition between the given levels.


• Relation between Einstein coefficients:
  n 2 c 3

g1B12=g2,821, B21 (^) kw3A21.

• Diagram showing formation of X-ray spectra (Fig. 6.8).


• Moseley's law for K, lines:
  K = 3 LI s^
  a 4 (Z— o)^2 ,

(6.3d)

(6.3e)

(6.3f)