Re: CCL:polyene spectra

["William F. Polik" <polik-0at0-hope.edu>]

 Ulrike,
This is a very common physical chemistry experiment illustrating the
 Particle-in-a-Box that is described in most physical chemistry
 laboratory
 textbooks, as well as in several articles in the Journal of Chemical
 education over the last decade.
You can find several references to the older literature in Chapter 11
 of
 Jaffe & Orchin, "Theory and Applications of UV
 Spectroscopy".  One article
 in particular that derives this result is
   H. Kuhn, Journal of Chemical Physics, vol 17, p. 1198 (1949)
 At 02:38 AM 11/1/02, you wrote:
> in the literature it is commonly stated that UV
>  absorbtion energies of
>  polyenes with increasing chain lengths decrease approximately linearly
>  when plotted against 1/n, the number of repeat units. Does anyone know
>  where this has been stated for the first time and at which level of
>  theory
>  this is true exactly. I am writing a paper and I want to give a proper
>  reference, however, usually people do not give a citation or they just
>  cite their own previous papers. I suspect that the relationship does
>  not
>  necessarily hold when higher levels of theory are used and when the
>  geometries are optimized. Can somebody comment on this?
>  
 Will Polik