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We systematically studied the vibrational-resolved electronic spectra of group IV dichlorides using the Franck–Condon approximation combined with the Duschinsky and Herzberg–Teller effects in harmonic and anharmonic frameworks (only the simulation of absorption spectra includes the anharmonicity). Calculated results showed that the band shapes of simulated spectra are in accordance with those of the corresponding experimental or theoretical ones. We found that the symmetric bend mode in progression of absorption is the most active one, whereas the main contributor in photoelectron spectra is the symmetric stretching mode. Moreover, the Duschinsky and anharmonic effects exert weak influence on the absorption spectra, except for PbCl 2 molecule. The theoretical insights presented in this work are significant in understanding the photophysical properties of MCl 2 (M = C, Si, Ge, Sn, Pb) and studying the Herzberg–Teller and the anharmonic effects on the absorption spectra of new dichlorides of this main group. [ABSTRACT FROM AUTHOR]

Abstract: Two types of dinuclear copper(II) and nickel(II) complexes with two tetradentate N2O2 donor ligands 1,4-bis(1-anthranoylhydrazonoethyl)benzene (L1), 1,4-bis(1-salicyloylhydrazonoethyl)benzene (L2) and N,N′-bidentate heterocyclic base [1,10-phenonthroline (phen)] have been synthesized and characterized by elemental analysis, infrared spectra, UV–vis electronic absorption spectra and magnetic susceptibility measurements. The reaction of metal(II) acetates with the solution containing ligand and 1,10-phenonthroline in methanol gives mixed-ligand dinuclear metal(II) complexes with general formula [M2L(phen)2]Cl2 (L=L1 or L2), whereas, the ligands react with metal(II) acetates to form polymeric dinuclear complexes with general formula [(M2L2) n ] (L=L1 or L2). In the complexes, the ligands act as dianionic tetradentate and coordination takes place in the enol tautomeric form with the enolic oxygen and azomethine nitrogen atoms while the phenolic hydroxyl and amino groups of aroylhydrazone moiety do not participate in coordination. The effect of varying pH and solvent on the absorption behavior of both ligands and complexes has been investigated. [Copyright &y& Elsevier]

From the critical analyses of Raman and infrared spectra, different normal modes of vibration of diphenylmethane (DPM) have been identified. The near ultraviolet absorption spectra of the molecule are found to consist of two band systems, one around 220 nm and the other around 270 nm with respective f-values 5.23×10-2 and 6.44×10-3. The first system is broad and shows few diffuse structures, whereas the later one exhibits very well-resolved structure. They are respectively assigned as 1La and 1Lb bands. The Raman excitation profiles of several normal modes have been analyzed to get structural and other information of different excited electronic states. [Copyright &y& Elsevier]