Poetry of Physics and the Physics of Poetry

180 The Poetry of Physics and The Physics of Poetry

172 The Poetry of Physics and The Physics of Poetry

model actually occur experimentally.

Fig. 19.1 The Bohr Atom

Bohr's model was unable to predict which transitions were forbidden.

Ironically, the classical theory, which is unable to explain the observed

frequencies of the atom, is, however, unlike the Bohr theory, able to

calculate the relative intensity of lines, the polarization and the forbidden

transitions. In order to compensate for the deficiency of his model, Bohr

incorporated the positive features of the classical theory into his scheme

through the correspondence principle.

Bohr noticed that for the atomic transition among the more highly

excited states that the difference in energy between the two adjacent

levels becomes progressively smaller as the energy increases. He also

noticed that the difference in the orbital radii also becomes smaller. As

one goes to higher energies the transitions from adjacent levels becomes

continuous as is the case in the classical theory. This is easily seen by

examining the formula for the energy, En, of the nth atomic level En = -

hRy/n^2 = -E 1 /n^2.

The energy for all the atomic levels is negative. The reason for this is

that the potential energy is negative and greater in magnitude than the

kinetic energy (1/2mv^2 ), which, naturally is positive. As long as the

electron is orbiting the atom and hence, bound to it, its total energy will

be negative. If its total energy ever becomes positive then it will no

longer be bound to its nucleus. When referring to high-en ergy atomic

level we will be discussing those levels for which n is large and,

consequently, the energy En is almost zero but still negative. For these

high energy levels, the difference between the nth level and the (n-1)th

level is given approximately by En - En-1 = 2hRy/n^3 , which goes to zero as

• 
  

  –

  
  

Fig. 19.1 The Bohr Atom

Bohr’s model was unable to predict which transitions were forbidden.
Ironically, the classical theory, which is unable to explain the observed
frequencies of the atom, is, however, unlike the Bohr theory, able to
calculate the relative intensity of lines, the polarization and the forbidden
transitions. In order to compensate for the deficiency of his model, Bohr
incorporated the positive features of the classical theory into his scheme
through the correspondence principle.
Bohr noticed that for the atomic transition among the more highly
excited states that the difference in energy between the two adjacent
levels becomes progressively smaller as the energy increases. He also
noticed that the difference in the orbital radii also becomes smaller.
As one goes to higher energies the transitions from adjacent levels
becomes continuous as is the case in the classical theory. This is easily
seen by examining the formula for the energy, En, of the nth atomic level
En = – hRy/n^2 = – E 1 /n^2.
The energy for all the atomic levels is negative. The reason for this is
that the potential energy is negative and greater in magnitude than the
kinetic energy (1/2mv^2 ), which, naturally is positive. As long as the
electron is orbiting the atom and hence, bound to it, its total energy will
be negative. If its total energy ever becomes positive then it will no
longer be bound to its nucleus. When referring to high-energy atomic
level we will be discussing those levels for which n is large and,
consequently, the energy En is almost zero but still negative. For these
high energy levels, the difference between the nth level and the (n – 1)th
level is given approximately by En – En-1 = 2hRy/n^3 , which goes to zero as
n increases more rapidly than the energy En itself.