L A Morgan

Bio: L A Morgan is an academic researcher from Royal Holloway, University of London. The author has contributed to research in topics: Excited state & Scattering. The author has an hindex of 22, co-authored 36 publications receiving 1550 citations. Previous affiliations of L A Morgan include University of London & University College London.

R-matrix calculations for polyatomic molecules: electron scattering by

Abstract: A new computer program has been developed which allows us to use the R-matrix method to study electron scattering by polyatomic molecules. Our first application is to scattering by in its linear, equilibrium geometry for energies up to 10 eV. We confirm the earlier assignment of symmetry to the resonance near 2 eV but we are unable to locate any resonance having symmetry in this energy range. We present integral and differential cross sections which are generally in excellent agreement with experiment.

Electron scattering by nitrogen molecules

Abstract: The differential elastic and vibrationally inelastic cross sections for e-N2 scattering are calculated in the energy range from threshold to 30 eV using the R-matrix method. At low energies the cross sections are dominated by the well known 2 Pi g resonance. In this energy region non-adiabatic effects due to the coupling of the electronic and nuclear degrees of freedom are included. At higher energies the cross sections are dominated by the 2 Sigma u resonance. In this energy region the adiabatic approximation is appropriate. The cross sections are compared where possible with experiment. In general good agreement is obtained but some discrepancies suggest directions for future work.

Bound states using the R-matrix method: Rydberg states of HeH

Abstract: A method is presented for adapting scattering calculations performed with the molecular R-matrix method to find bound states based on the atomic method of Seaton. Quantum defect theory is used to determine initial energy grids and to determine whether all the bound states have been located. This method is particularly suited to the Rydberg states of electron plus molecular ion systems. The authors calculate and assign the lowest 33 electronic states of the HeH molecule. Previously on 14 of the lowest (n<5) bound states have been fully characterized, with several states omitted. They suggest that the omitted states give rise to some of the observed but previously unexplained weak transitions. Vibrational motion is included in their calculations within the adiabatic approximations. Effects arising from short-range correlations and nuclear motion are shown to be very significant for the lowest electronic states. Transition energies amongst the excited states agree with accurate spectroscopic determinations to better than 50 cm.

Theory and Experiment

Abstract: This paper studies the impact of ambiguity and ambiguity aversion on equilibrium asset prices and portfolio holdings in competitive financial markets. It argues that attitudes toward ambiguity are heterogeneous across the population, just as attitudes toward risk are heterogeneous across the population, but that heterogeneity of attitudes toward ambiguity has different implications than heterogeneity of attitudes toward risk. In particular, when some state probabilities are not known, agents who are sufficiently ambiguity averse find open sets of prices for which they refuse to hold an ambiguous portfolio. This suggests a different cross-section of portfolio choices, a wider range of state price/probability ratios and different rankings of state price/probability ratios than would be predicted if state probabilities were known. Experiments confirm all of these suggestions. Our findings contradict the claim that investors who have cognitive biases do not affect prices because they are infra-marginal: ambiguity averse investors have an indirect effect on prices because they change the per-capita amount of risk that is to be shared among the marginal investors. Our experimental data also suggest a positive correlation between risk aversion and ambiguity aversion that might explain the “value effect” in historical data.

Role of water in electron-initiated processes and radical chemistry: issues and scientific advances.

Abstract: Chemical Science Division, Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352; Department of Chemistry, ShelbyHall, University of Alabama, Box 870336, Tuscaloosa, Alabama 35487-0336; Notre Dame Radiation Laboratory, University of Notre Dame,Notre Dame, Indiana 46556; Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 0520-8107; Argonne NationalLaboratory, 9700 South Cass Avenue, Argonne, Illinois 60439; Department of Computer Science and Department of Physics, 2710 University Drive,Washington State University, Richland, Washington 99352-1671; Lawrence Berkeley National Laboratory, 1 Cyclotron Road Mailstop 1-0472,Berkeley, California 94720; Department of Chemistry and Biochemistry, University of Texas at Austin, 1 University Station A5300,Austin, Texas 78712; Office of Basic Energy Sciences, U.S. Department of Energy, SC-141/Germantown Building, 1000 Independence Avenue,S.W., Washington, D.C. 20585-1290; Department of Physics and Engineering Physics, Stevens Institute of Technology, Castle Point on Hudson,Hoboken, New Jersey 07030; Department of Chemistry, Johns Hopkins University, 34th and Charles Streets, Baltimore, Maryland 21218;Department of Chemistry, University of Southern California, Los Angeles, California 90089-1062; Department of Chemistry, The Ohio StateUniversity, 100 West 18th Avenue, Columbus, Ohio 43210-1185; Department of Chemistry, Columbia University, Box 3107, Havemeyer Hall,New York, New York 10027; Department of Chemistry, University of Pittsburgh, Parkman Avenue and University Drive,Pittsburgh, Pennsylvania 15260; Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000; Department of Physics andAstronomy, Rutgers, The State University of New Jersey, 136 Frelinghuysen Road, Piscataway, New Jersey 08854-8019; Department of Chemistry,516 Rowland Hall, University of California, Irvine, Irvine, California 92697-2025; Stanford Synchrotron Radiation Laboratory, Stanford LinearAccelerator Center, 2575 Sand Hill Road, Mail Stop 69, Menlo Park, California 94025; School of Chemistry and Biochemistry, Georgia Institute ofTechnology, 770 State Street, Atlanta, Georgia 30332-0400; Geology Department, University of California, Davis, One Shields Avenue,Davis, California 95616-8605; Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue,Cambridge, Massachusetts 02139-4307; Department of Chemistry, Purdue University, 560 Oval Drive, West Lafayette, Indiana 47907-2084Received July 23, 2004

Universal Gaussian basis sets for an optimum representation of Rydberg and continuum wavefunctions

Abstract: A universal Gaussian basis set concept for the calculation of Rydberg and continuum states by pure L2 methods is presented It is based on the generation of optimised sequences of Gaussian exponents by maximising the overlap with a series of Slater-type functions characterised by a constant exponent and a variable principal quantum number In this way linear combinations of Gaussian basis functions can be found which are ideally suited to imitate Laguerre-Slater functions It is thus possible to obtain optimum representations of Rydberg orbitals or of complete orthonormal systems of Laguerre functions playing an important role in the L2 expansion of continuum functions The basis sets are tested with the hydrogen atom The effectiveness of the basis is illustrated by the calculation of quantum defects associated with the s, p and d Rydberg series of the alkali metal atoms Li and Na The phaseshifts determined in the ionisation continuat of these systems nicely fit the series below the ionisation limit as is finally demonstrated by an Edlen plot