[en] The critical field strength is calculated at which the barrier disappears for an electron located in the field of a coulomb center and characterized by prescribed parabolic quantum numbers. The highly excited atoms lifetime in dependence on the field strength deviation from the critical value are obtained. The decay dynamics of highly excited atoms on passage of a beam of highly excited atoms through an electric field is investigated. The experimental data on ionization of highly excited atoms in an electric field are analyzed

[en] The properties of ¹⁷⁶Lu as a cosmos-chronometer and a cosmos-thermometer have been studied by the Coulomb excitation technique combined with the recoil method. As expected, the results show that this isotope can not be a reliable cosmos-chronometer. Furthermore it seems that its synthesis occurs for temperatures between 2.35 and 3.6 10⁸ K. The identification of the excitation levels is not easy because of their weak transition probability

[en] A method is described for selectively exciting and separating a selected isotope from a mixture of isotopes particularly useful in separation of isotopes of uranium and other heavy metals, including placing the mixture of isotopes in an excited gaseous state, selectively de-exciting, by means of stimulated emission, one or more isotopes of the mixture leaving the selected isotope in the excited state, and subsequently permanently separating the de-excited and excited isotopes. (author)

[en] The core hole localization, multiplets in the singly core-excited state, and their Auger-like two-electron de-excitation are discussed in some diatomic systems from the viewpoint of the exchange interaction. The exchange repulsion arising from the core-core overlap is proved very small, indicating that the core electron is essentially localized on a specified atom, even in homonuclear systems. Relatively large core-valence exchange interaction between the adjacent atoms results in observable 1sσ_g-σ_u splittings in N₂ and C₂H₂. The 1s→π* excitation of a doublet radical NO gives three different electronic states. The ²Σ^- state energy relative to the ²Δ and ²Σ⁺ states is dependent on the exchange integral between the core and π* electrons. The two dipole-allowed ²Π 1s→σ* excited states of NO are characterized by singlet and triplet couplings between two of the three open-shell electrons. In the N 1s excitation, the σ* and π* electrons are strongly coupled with the triplet and singlet spins. In the O 1s, the core and π* electrons are weakly coupled; then, the singlet-coupled is lower in energy and weaker in intensity than the triplet. Triplet radicals O₂, S₂, and Se₂ have two dipole-allowed ³Σ_u^- 1s→σ* excited states with four open shells, which are characterized by doublet and quartet couplings among three of the four electrons. In the S and Se 1s excitations, the σ* and two π* electrons are relatively strongly coupled with the quartet and doublet spins. In the O 1s, the core and two π* electrons are weakly coupled; then, the doublet-coupled is lower in energy and weaker in intensity than the quartet. In the resonant photoionization via the 1s→π* and 1s→σ* excited states in NO and O₂, the two-electron de-excitation selection and propensity rules are discussed in terms of state symmetry, spin multiplet and S_z value. In the case that the two electrons taking part in the de-excitation have the same spins, additional exchange-type interaction reduces the transition probability

[en] Inelastic, charge-exchange and transfer reactions induced by hadronic probes at intermediate energies have revealed a rich spectrum of new high-lying modes embedded in the nuclear continuum. The investigation of their decay properties is believed to be a severe test of their microscopic structure as predicted by nuclear models. In addition the degree of damping of these simple modes in the nuclear continuum can be obtained by means of the measured branching ratios to the various decay channels as compared to statistical model calculations. As illustrative examples the decay modes of high-spin single-particle states and isovector resonances will be discussed. (author). 23 refs., 14 figs

No abstract available

[en] Energies and excitation probabilities for collective dipole states of negative parity are calculated using the Skyrme forces. The Wigner function moment method is used in the calculations. The giant dipole resonance, high-lying isoscalar and isovector compressional modes, and low-lying modes, which were discovered recently, are described well by the theory. 16 refs., 2 figs., 3 tabs

[en] The excitation of the singlet S and P deg. levels of a Sr atom from the ground state by slow electrons was studied by the method of extended crossing beams. It was ascertained that perturbations manifest themselves in the behavior of the excitation cross sections in the spectral series arising as a result of the transitions from these levels. The perturbations affect to a larger extent the form of the optical excitation functions rather than the absolute values of the cross sections. The results obtained are compared with previous data

[en] Despite the concept of nuclear spin isomers (NSIs) exists since the early days of quantum mechanics, only few approaches have been suggested to separate different NSIs. Here, a method is proposed to discriminate different NSIs of a quinodimethane derivative using its electronic excited state dynamics. After electronic excitation by a laser field with femtosecond time duration, a difference in the behavior of several quantum mechanical operators can be observed. A pump-probe experimental approach for separating these different NSIs is then proposed

[en] The spectral behaviour of a pharmaceutically important molecule, 1-(2-Hydroxy-5-bromo-phenyl)-3,5-dioxo-1H-imidazo-[3,4-b] isoindole (ADBR), has been reported. The photophysical properties of ADBR reveal the occurrence of excited state intramolecular proton transfer (ESIPT) phenomenon involving a four-membered system, resulting in a conversion from lactim to lactam form of ADBR in the excited state. Excitation at shorter wavelength resulted in dual emission from ADBR in water due to the presence of the proton transferred (lactam) form along with the excited local (lactim) form, although, only PT emission was observed in all other solvents of varying polarity used in this study. The ESIPT process was found to be hindered in water probably due to intermolecular hydrogen bonding between the water molecules and the functional groups of lactim form of ADBR involved in the ESIPT phenomenon. The time-resolved studies corroborated the steady state data and confirmed the operation of an ultrafast ESIPT process.