Electron Scattering from Gaseous Ocs(1Σ^1\Sigma): Comparing Computed Angular Distributions and Elastic Cross Sections with Experiments

Differential cross sections are computed for the title polar molecule using static interaction, exchange forces and correlation-polarisation effects as described in detail in the main text. The dipole effect is also reported via the dipole Born correction procedure and the final angular distributions are compared with existing experimental data. The shape and location of the prominent low-energy resonance are computed and compared with experiments. The comparison shows that the present treatment of the interaction forces and of the quantum dynamics can indeed afford good agreement between measured and computed quantities for a multielectron target as OCS

FERM3D: A finite element R-matrix electron molecule scattering code

FERM3D is a three-dimensional finite element program, for the elastic scattering of a low energy electron from a general polyatomic molecule, which is converted to a potential scattering problem. The code is based on tricubic polynomials in spherical coordinates. The electron-molecule interaction is treated as a sum of three terms: electrostatic, exchange. and polarisation. The electrostatic term can be extracted directly from ab initio codes ({\sc{GAUSSIAN 98}} in the work described here), while the exchange term is approximated using a local density functional. A local polarisation potential based on density functional theory [C. Lee, W. Yang and R. G. Parr, {Phys. Rev. B} {37}, (1988) 785] describes the long range attraction to the molecular target induced by the scattering electron. Photoionisation calculations are also possible and illustrated in the present work. The generality and simplicity of the approach is important in extending electron-scattering calculations to more complex targets than it is possible with other methods.Comment: 30 pages, 4 figures, preprint, Computer Physics Communications (in press

Ultralow-energy vibrational quenching in ionic collisions: Isotope effects in Li+ + D2 encounters

he collisional, superelastic encounters at ultralow energies of Li(+) with D(2) are computed using the exact coupled-channel dynamics, and using an ab initio potential energy surface discussed in earlier work. The changes in the target rovibrational structure due to the isotopic substitution, and in its rovibrational wave functions, are seen to have a marked effect, under the collision conditions of vanishing relative energy, on the corresponding dynamical attributes, allowing one to make specific predictions on the possible use of isotopic variants in cold trap processes

Collisional Quenching at Ultralow Energies: Controlling Efficiency with Internal State Selection

Calculations have been carried out for the vibrational quenching of excited H$_2$ molecules which collide with Li$^+$ ions at ultralow energies. The dynamics has been treated exactly using the well known quantum coupled-channel expansions over different initial vibrational levels. The overall interaction potential has been obtained from the calculations carried out earlier in our group using highly correlated ab initio methods. The results indicate that specific features of the scattering observables, e.g. the appearance of Ramsauer-Townsend minima in elastic channel cross sections and the marked increase of the cooling rates from specific initial states, can be linked to potential properties at vanishing energies (sign and size of scattering lengths) and to the presence of either virtual states or bound states. The suggestion is made that by selecting the initial state preparation of the molecular partners, the ionic interactions would be amenable to controlling quenching efficiency at ultralow energies

Schemes of Funding Music Research in Italy: A Case Study in Comparison with other European Countries

The awareness of the central government and other supportive agencies in Italy as to the need for research to be accomplished in music and music history in that country is determined by first stating what that support has been for such research in the 1990s, together with its accessibility to groups and/or individuals working in that field, and then reporting how such aid has been reduced in the more recent times of financial crises. In order to assess Italy's position not in isolation but more realistically by considering it within a broader geographical frame, the same investigation has been accomplished for a group of other culturally developed countries in Europe which offer sufficient areas of comparison: Spain, France, England, Germany. Sadly, Italy does not come off well. Perhaps surprisingly but still sadly this is shown not to be due to the present financial crises but to a long-standing absence of respect for the entire musical history of the country and for the need that it be known and understood thoroughly. In short, the government in Italy seems not to have been sufficiently aware of its responsibility to acknowledge and preserve its musical patrimony by adequately supporting research which aims at uncovering the country's rich past, understanding it, and thereby making it available to professional performing musicians and, through them, also to the people of Italy and the rest of the world

Application of the zero-range potential model to positron annihilation on molecules

In this paper we use a zero-range potential (ZRP) method to model positron interaction with molecules. This allows us to investigate the effect of molecular vibrations on positron-molecule annihilation using the van der Waals dimer Kr2 as an example. We also use the ZRP to explore positron binding to polyatomics and examine the dependence of the binding energy on the size of the molecule for alkanes. We find that a second bound state appears for a molecule with ten carbons, similar to recent experimental evidence for such a state emerging in alkanes with twelve carbons.Comment: 14 pages, 6 figures, to be published in Nuclear Instruments and Methods