Re: dielectric constant

[Roger Haar <haar@PHYSICS.ARIZONA.EDU>]

Hi,

        I only have the second addition of Hecht in front
of me so I am a bit unsure of the numbering of
figures and tables.  But at least in the second
addition Hecht presents a far discussion about the
theoretic form of the frequency dependent
dielectric constant. This implies that the theory
is probably pretty good.

        The big thing (for diffuse gases) that is left
out is how one gets the oscillator strengths.
These are associated with John Denker's line
shapes.  In solids, the correlations and effect of
the electric field caused by the neighbors also
become important.

        Overall, textbooks are not that good at
indicating the current level of understanding of
physics.

Thanks
Roger
Haar

****************************

Ludwik Kowalski wrote:
> "John S. Denker" wrote:
> >
SNIP

> > What's the evidence for this inability?  Spectroscopy
> > is a pretty well-established discipline.  Spectroscopists
> > have been calculating lineshapes to high accuracy for a
> > long time.  Really high accuracy.
>
> I have no evidence. My feeling is justified by the absence
> of clear statements in textbooks. For example, something
> like this: " the wavelength dependence of n for glass or
> water can be very accurately calculated in QED."
>
> The line shape, I suppose, depends on parameters of two
> levels. How can this be translated into the frequency
> dependence of n or K?
> Ludwik Kowalski