Conjugated organic molecules spectra

In this review, we explain the SAC-CI applications to molecular spectroscopy with some examples. In Section 2, we briefly explain the theoretical and computational aspects of the SAC-CI method. Then, we show some SAC-CI applications to molecular spectroscopy the excitation and ionization spectra of tt-conjugated organic molecules (Section 3), collision-induced absorption spectra of van der Waals complex (Section 4), excitation spectra and NMR chemical shifts of transition metal complexes (Section 5), photofragmentation reaction of Ni(CO)4 (Section 6), absorption spectrum of free-base phthalocyanine (FBPc) and bacterial photosynthetic reaction center... 

The absorption spectrum of most molecules is simple, stable and considered intrinsic to the material. The resonant conjugated organics conform to these conditions with regard to their intrinsic absorption spectra. However, as they achieve the condition described by (7P) and (8R), they exhibit an additional absorption spectrum. This additional spectrum is poorly defined in mathematical terms under condition (7P) because the size of the clusters is highly dependent on the exact molarity of the solution and other parameters determining this parameter. It is more easily defined in (8R) because the size of the film is more easily characterized. 

Conjugation of two chromophores not only results in a bathochromic shift but increases the intensity of the absorption. These two effects are of prime importance in the use and interpretation of eleetronic spectra of organic molecules, because conjugation shifts the selective light absorption of isolated chromophores from a region of the spectrum that is not readily accessible to a region that is... 

Acrolein is a small organic molecule with some very interesting features. It can be considered as a prototype of molecular systems containing two conjugated chromo-phores, namely C=C and C=0, a common feature for many natural molecules. Also, the presence of two characteristic functional groups at the same time has important consequences in the chemistry and photochemistry of acrolein. For these reasons, its UV absorption spectrum has been extensively studied in different solvents [104—110] as well as in the gas phase [111-113], and a solvatochromic blue shift of the n —> n transition of the C=0 group has been observed in going from the gas phase to aqueous... 

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