CCL: UV-Vis calculations

[errol lewars <elewars,+,trentu.ca>]

 Sent to CCL by: errol lewars [elewars:trentu.ca]
 2007 June 26
I don't know what your results for biphenyl look like, but TDDFT or
 CIS
 calculations could easilily be out by 20 nm or so,  and signals of zero
 oscillator strength actually show up in the experimental UV as weak
 absorptions, because of vibrational distortions from perfect symmetry.
 To get a feel for this do some calculations on small molecules and
 compare the calculated and exp UVs. The "solution" to your
 problem is to
 be allow for the errors in the calculations.
 E. Lewars
 ===
 Pedro David Ortiz pedrod-$-fq.uh.cu wrote:
>  Sent to CCL by: "Pedro David Ortiz" [pedrod/./fq.uh.cu]
>  Dear CCL:
> Im trying to do UV-Vis calculations of C6H5-C6H5 by using DFT TD and
>  CIS.  I have obteined very but results with bouth methods: in the range of
>  energy corresponding to experimental absortion there are not signals with
>  significat oscilator strength. All comments about solutions will be very
>  appreciated.
>  
>  Thanks in advance.>
>  
>