[en] Short communication

No abstract available

[en] The structure and properties of H₃/sup+/ ions in magnetic fields with strength of the order of 10⁹--10¹⁰ G have been studied by means of a variational method. It is found that there is a rapid change in the configuration of the H₃/sup+/ ion from its equilateral triangular structure to a linear chain, around a magnetic field B/sub c/ = 2.35 x 10⁹ G. The exchange contribution increases with the magnetic field, and its effect on B/sub c/ is to lower its value. The vibrational frequencies of H₃/sup+/, about its ground-state structure increase with the field strength and undergo a rapid change near B/sub c/. The oscillator strengths for the electronic transition stay nearly constant in the range 0--4.7 x 10¹⁰ G of the magnetic field strength studied

No abstract available

[en] Stability diagrams for a series of ionic species trapped within the QUISTOR are obtained under various experimental conditions. The extent to which the boundaries of the diagrams are displaced from their theoretical positions is discussed in terms if existing models for the influence of space charge upon ion stability. Whilst space-charge within the trapped ion cloud does appear to exert an effect there is evidence of some, as yet unexplained, additional factor causing destabilisation. (orig.)

[en] We develop an efficient method for the calculation of corrections to the Born-Oppenheimer approximation by means of perturbation theory. The perturbation terms through sixth order in the small parameter κ=(m/M)^1/4, where m and M are, respectively, electronic and nuclear masses, allow the construction of an effective vibrational Hamiltonian that takes into account adiabatic and nonadiabatic effects. The latter is negative and linearly dependent on the vibrational quantum numbers. We illustrate the application of the main equations and verify the general results by means of an exactly solvable model of two coupled harmonic oscillators

No abstract available

[en] A large number of full CI calculations has been performed in order to obtain an accurate representation of the potential energy surface of the molecular ion H⁺₃ in its lowest triplet state. It is found that the surface is very flat, so that the molecule is very floppy and has a great likelihood of tunneling between the three symmetry-related minima. The potential is expanded in terms of elements of Wigner D matrices depending on hyperspherical angles. An extensive discussion of the Smith--Whitten hyperspherical coordinates, used in this work, is given

No abstract available

[en] Short communication