Absorption bands in the visible region of the spectrum (350 700 nm) correspond to transitions from the ground state of a molecule to an excited electronic state which is 160 to 280 kJ above the ground state. In many substances, the lowest excited electronic state is more than 280 kJ above the ground state and no visible spectrum is observed. Those compounds which are colored (i.e., absorb in th...

Excited-state potentials of a short protonated Schiff base cation which serves as a model for the photoisomerization of retinal are computed by combining a semi-empirical ground-state adiabatic surface with excitation energies obtained using the time-dependent coupled electronic oscillator ~CEO! approach. Excited-state molecular dynamic simulation of the in-plane motion of cis-C5H6NH2 1 followi...

The electronic structure of a molecule determines such physical and chemical properties as its charge distribution, geometry (and therefore the dipole moment), ionization potential, electron affinity, and of course, chemical reactivity. If the electronic structure of a molecule were to be changed, one would expect its physical and chemical properties to be altered. Such a rearrangement can occu...

The electronic structure of a molecule determines such physical and chemical properties as its charge distribution, geometry (and therefore the dipole moment), ionization potential, electron affinity, and of course, chemical reactivity. If the electronic structure of a molecule were to be changed, one would expect its physical and chemical properties to be altered. Such a rearrangement can occu...

Nuclear spins are efficient probes of electronic states. Because most NMR experiments are performed in thermal equilibrium, they probe the electronic ground state—the only state that is significantly populated under ambient conditions. Probing electronically excited states becomes possible, if magnetic resonance techniques are combined with optical (laser) excitation. Depending on the nature of...

We compare the electronic temperatures and the population inversion both below and above the lasing threshold in three quantum-cascade lasers sQCLsd operating at 2.8 THz, 3.2 THz, and 3.8 THz using microprobe band-to-band photoluminescence. In the lasing range, while the ground-state temperature remains close to the lattice one s90 K–100 Kd, the upper radiative state heats up to ,200 K. From th...

The electronic spectrum of the UO(2) molecule has been determined using multiconfigurational wave functions together with the inclusion spin-orbit coupling. The molecule has been found to have a (5fphi)(7s), (3)Phi(2u), ground state. The lowest state of gerade symmetry,( 3)H(4g), corresponding to the electronic configuration (5f)(2) was found 3330 cm(-1) above the ground state. The computed ene...