Theoretical study of the CC stretching vibrations in linked polyene chains: Nystatin

Theoretical analysis of spectra of short polyenes

“…Thus the resonance Raman spectrum of nystatin shows two tetraenic fundamentals in the C=C stretch region,224 one being the highest frequency in-phase stretch, active in all polyenes, the second other being the lower frequency out-of-phase stretch. 150 The interaction between these two modes via the diene unit leads to an increase in frequency of the strongly active in-phase C=C stretching mode.…”

Ab Initio Calculations of Vibronic Spectra and Dynamics for Small Polyatomic Molecules: Role of Duschinsky Effect

“…As mentioned above, the same group used a similar approach to study the vibronic spectra of cis - and trans -hexatriene . Zerbetto and Zgiersky are particularly active in this field; they employed the QCFF-PI and CNDO/S+CISD method to investigate the spectroscopic behavior of various polyenes such as anthracene, nystatin, and butadiene. − More recent applications based on semiempirical potential energy surfaces include the calculation of the Duschinsky effect in phenol by Venuti and Marconi and the study of 1,3,5-tri- tert -butylpentalene by Falchi et al Studies based on ab initio potential energy surfaces have appeared only recently and are still rare. Chau et al studied the vibrational structure of the He I photoelectron spectrum of H 2 Se based on the high-level CCSD(T) geometry optimization and harmonic vibrational frequency computation and used Chen's method to compute the Franck−Condon factors.…”