The longest-wavelength π-to-π* electronic excitations of rhodamine-like dyes (RDs) with different group 16 heteroatoms (O, S, Se, Te) have been investigated. Time-dependent Kohn-Sham theory (TDKST) calculations were compared with coupled-cluster (CC) and equations-of-motion (EOM) CC results for π-to-π* singlet and triplet excitations. The RDs exhibit characteristics in the TDKST calculations th...

Using parameter values relevant to polyacetylene and its finite polyene analogs, we determine, via exact finite size diagonalization of a 1D Peierls-Hubbard model, the relaxed geometry and optical absorption spectra of several states of interest in optical experiments (the singlet (1Ag) and triplet (1Bu) ground states, the singlet one (n Bu) and two (2 Ag) photon gaps, and the triplet one (n Ag...

Photolysis of N-benzoyl-S,S-diphenylsulfilimine or N-benzoyl dibenzothiophene sulfilimine produces PhNCO and also benzoylnitrene. Direct observation of the triplet nitrene, energetic differences between the singlet and triplet state of the nitrene, and oxygen quenching experiments suggest that the triplet nitrene derives from the triplet excited state of the sulfilimine precursors, rather than ...

Gaussian-2 and QCI theory with basis sets up to 6-311+G(3df,2p) have been employed to obtain information about the carbenes (methylenes) CH2, CHBr, CHCl, CHF, CHI, CBr2, CBrCl, CBrF, CBrI, CCl2, CClF, CClI, CF2, and CI2. Geometries and vibrational frequencies for the singlet and triplet states, and the singlet-triplet splittings, have been characterized and are discussed in the context of the e...

We have measured and fitted the kinetics of luminescence of Ag nanoclusters homogeneously dispersed within the bulk of an oxyfluoride glass, with various sample temperatures. The balance equations for the populations of the excited singlet and triplet states of the Ag nanoclusters are proposed and used in this fitting while taking into account inter-system crossing between the singlet and tripl...

The organic-inorganic hybrid quantum well compound, (C10H7C2H4NH3)2PbCl4, exhibits enhanced phosphorescence due to the energy transfer from the excitonic state of inorganic quantum well to the triplet state of naphthalene chromophore. In the present study, photoluminescence and optical absorption spectra of (C10H7C2H4NH3)2PbCl4 were investigated under pressure to 6.5 GPa in order to investigate...

The carbon dimer, the C2 molecule, is ubiquitous in astronomical environments. Experimental-quality rovibronic energy levels are reported for C2, based on rovibronic transitions measured for and among its singlet, triplet, and quintet electronic states, reported in 42 publications. The determination utilizes the Measured Active RotationalVibrational Energy Levels (MARVEL) technique. The 23,343 ...

The influence of halogen atom substitution (Br and I), in different amounts and positions in an aza-BODIPY skeleton, on the photophysical properties of some aza-BODIPY derivatives has been investigated by using density functional theory and its time-dependent extension. The heavy atom effect on excitation energies, singlet-triplet energy gaps and spin-orbit matrix elements has been considered. ...

We introduce a broadly applicable technique to create nuclear spin singlet states in organic molecules and other many-atom systems. We employ a novel pulse sequence to produce a spin-lock induced crossing (SLIC) of the spin singlet and triplet energy levels, which enables triplet-singlet polarization transfer and singlet-state preparation. We demonstrate the utility of the SLIC method by produc...