Re: dielectric constant

["John S. Denker" <jsd@MONMOUTH.COM>]

Ludwik Kowalski wrote:
> I also notice a discrepancy between the plots of
> n versus w. In Feynman (page 31-8, vol I) n=1
> at very law w, which is not true if we identify n
> with the square root of the dielectric constant, K.

What's the discrepancy?

> Only in gasses is K very close to unity at w->0.

So why not conclude that figure 31-5 (on page 31-8)
represents a dilute gas?  Further evidence in support
of this conclusion comes from the fact that n peaks
at around n=2 or n=3;  in a dense substance it could
be a million or so.  Atomic resonances have high Q.

> Somehow I feel that nobody can
> calculate n(w) quantitatively to produce agreement
> with experimental data for real substances,

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.