Internal, generally excitation

Generally, excitation leads to excited singlet states (5j, S, etc.), which may be overlaid by vibrational energy levels. Higher excited singlet states usually deactivate by internal conversion (IC) very fast (within femtoseconds) to the lowest excited singlet state 5j. These 5j states are still very instable and have lifetimes in the nanosecond and picosecond range. Three photophysical processes of the state are typical ... 

Since the intramolecular motions can shift either to the blue or red the net Isotopic difference of the shifts can be either positive or negative, and can therefore lead to positive (normal) or negative (inverse) VPIEs. In general, excitation Into upper vibrational levels must be considered and these contributions can lead to complicated temperature dependencies (14). Some of the Ideas outlined above are presented In a conventional schematic fashion In Figure 1. Diagrams are given for both Internal and external modes. 

The zeroth-order Hamiltonian of the CASPT2 theory is a projected generalized Fock operator, and the orthogonal functions are internally contracted excitations. In this case the resolvent operator is not diagonal, and thus its inverse is determined in an iterative process. To be able to perform the inversion of the resolvent operator efficiently,... 

D. of lead in brass by, 770 direct reading instruments, 775, 776 electrodes for, 763, 771 equipment for, 760, 764 excitation sources for, 763, 773, 774 general discussion of, 8, 758 internal standard method, 769 investign. of a complex inorganic mixture, 770... 

A number of fluorescent dyes with internal charge transfer mechanism allow the molecule to twist (rotate) between the electron donor and electron acceptor moieties of the fluorescent dipole. In most cases, the twisted conformation is energetically preferred in the excited Si state, whereas the molecule prefers a planar or near-planar conformation in the ground state. For this reason, photoexcitation induces a twisting motion, whereas relaxation to the ground state returns the molecule to the planar conformation. Moreover, the Si — So energy gap is generally smaller in the twisted conformation, and relaxation from the twisted state causes either a... 

---