The calculation of the ionization energies of CrOCl3 by configuration-interaction and ΔSCF methods

The calculation of the valence ionization energies of CrOCl₃ by a configuration-interaction method is described and compared with the He(I) and He(II) photoelectron spectra of this molecule. Such a calculation yields ionization energies in good agreement with experiment and is superior to the ΔSCF method which predicts the incorrect ground state of CrOCl⁺₃.     

The electronic structure of CrO3+ and MoO3+ complexes

The results of ab initio molecular orbital calculations for [CrOf_s]^2? and polarised single crystal electronic spectra of [MoOCl₃(Op(NMe₂)₃)₂] and Ph₄As[MoOCl₄(H₂O)] are presented. These data are consistent with the electronic transitions of the MO³⁺ moieties, O_2pπ → M_dxy and M_dxy → Md_dxy,dyz being the lowest energy transitions in the spectra of their respective complexes, both these transitions being of low intensity.     

Theoretical investigation of the symmetric trisubstituted borazines

The bonding in borazine and four symmetric tri-substituted derivatives, B-trifluoroborazine, N-trifluoroborazine, B-trimethylborazine and N-trimethylborazine, is discussed by means of all electron ab initio SCFMO calculations. B-trifluoroborazine is predicted to be 12·9 eV more stable than the N-trifluoro derivative and B-trimethylborazine 2·8 eV more stable than the N-trimethyl derivative. The calculated wavefunctions are used to interpret the low energy photoelectron spectra of these molecules. The calculated sequence for the three highest filled orbitals is πσπ in all derivatives except B-trifluoroborazine, where the sequence ππσ is realised.     

Symmetric prismatic tensegrity structures: Part I. Configuration and stability

This paper presents a simple and efficient method to determine the self-equilibrated configurations of prismatic tensegrity structures, nodes and members of which have dihedral symmetry. It is demonstrated that stability of this class of structures is not only directly related to the connectivity of members, but is also sensitive to their geometry (height/radius ratio), and is also dependent on the level of self-stress and stiffness of members. A catalogue of the structures with relatively small number of members is presented based on the stability investigations.     

Molecular simulation and the collaborative computational projects

The European Physical Journal H - In the late 1970s, the embryonic UK research community in molecular simulation – physicists and physical chemists – organised itself around CCP5, one...     

Femtosecond dynamics and coherent control in atoms, molecules and clusters: Theory and experiments

The understanding and control of the dynamics in atoms, molecules and clusters has been a tremendously growing field in the past decade. This has been acknowledged with the 1999 Nobel prize in chemistry awarded to Ahmed Zewail. The present issue collects some of the newest theoretical and experimental results in the field of ultrafast dynamics and coherent control in the gas phase. The papers are grouped into three categories. The first section contains work on the “Coherent Control with Femtosecond Laser Pulses”. Topics like the general theory of quantum control, the control of electron transfer processes, transformation of chiral molecules and coherent population transfer are treated here. The “Femtosecond Dynamics” taking place in molecules and clusters is the topic of the second section. New insight into the nature of atomic motion within molecules and relaxation processes is provided. The last section collects most recent work on the interaction of ultrashort laser pulses with matter. In particular, high harmonic generation, multi-photon ionization and interference effects, as well as the possible orientation of molecules in external fields are discussed. We think that the present compilation demonstrates that the field of ultrashort pulse spectroscopy is of still growing importance and exciting new phenomena have been revealed in the past and will be discovered in the future.