Re: Bohr's Atom still number one

On May 8, 12:50 am, a...@xxxxxxxxxxxxxxxxxxx (John Park) wrote:
bz (bz+...@xxxxxxxxxxxxxxxxxxxx) writes:
The_Man <me_so_hornee...@xxxxxxxxx> wrote in
[...]
Core electrons travel at approximately c/ Z, where Z is the
nuclear charge. When Z gets large, the speed of the electrons becomes
sufficiently close to c, so that relativistic effects become very
important.

Are such effects observed? Wouldn't the atomic mass be effected?

Effects are observed in the chemistry of the very heavy elements.
Iodine, which seems just like a really massive version of chlorine,
has distrinct properties as a result of relativistic effects. These
can be calculated with either the Dirac-Fock method, or the use of
relativistic effective pseudopotentials.


[...]
I don't think the velocity is ~c/Z (proportional to sqrt (Z) maybe), but
relativistic effects are observed, though usually rather subtle. They
influence the energy levels of heavy atoms (where the core, high-Z effect
is important) and, I seem to recall, are responsible for gold being yellow.

I stand corrected (I was typing off the top of my head)
The velocity of inner (core) electrons is (very) roughly100*Z/c, so
that the speed of inner core electrons for uranium is 92% c. The
formula is only vaguely acccurate - obviously, the electrons of
element 101 are not going faster than c. But it shows that
relativistic effects can't be ignored for very heavy elements (say Z
70).


--John Park


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Relevant Pages

  • Re: Bohrs Atom still number one
    ... has distrinct properties as a result of relativistic effects. ... The velocity of inner electrons is roughly100*Z/c, ... that the speed of inner core electrons for uranium is 92% c. ... The longitudinal mass would be about 16.6 ...
    (sci.physics.relativity)
  • Re: Bohrs Atom still number one
    ... nuclear charge. ... the speed of the electrons becomes ... relativistic effects are observed, though usually rather subtle. ... influence the energy levels of heavy atoms (where the core, ...
    (sci.physics.relativity)
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