A theoretical investigation of molecular core binding and relaxation energies in a series of oxygen-containing organic molecules of interest in the study of surface oxidation of polymers

Nonempirical LCAO MO SCF computations (in the ΔSCF formalism) have been carried out of binding energies and relaxation energies for an extensive series of oxygen-containing organic systems encompassing most of the common functionalities. The molecules for which experimental data are available for comparison demonstrate the adequacy of the treatment for describing the relative binding energies for both the C_ls and O_ls core levels. A sound basis is therefore provided for the discussion of relative core binding energies (C_ls and O_ls) for functionalities for which experimental data are not available, that is, hydroperoxides, peroxides, peroxyacids, and peroxyesters, a knowledge of which is essential for investigations of the surface oxidation of polymers by means of ESCA. C_ls shifts are discussed in terms of primary and secondary substituent effects of oxygen, which greatly simplify the analysis of complex unresolved spectra, whereas for the O_ls levels a similar but less straightforward situation exists. The relaxation energies associated with both C_ls and O_ls core ionization follow a dependence on the binding energy for a given structural type.     

A theoretical investigation of the electric field dependence of core ionization phenomena in carbon monoxide

The influence of an applied electric field on core binding and relaxation energies accompanying core ionization has been theoretically investigated by means of non-empirical LCAO MO SCF calculations within the ASCF formalism, on a simple prototype molecule (carbon monoxide). Single orbital contributions to the total relaxation energies, together with Mulliken population analyses and density difference contours, are presented. Investigations of the effect of an electric field on shake-up transitions, and potential energy surfaces, as evidenced by band profile analysis, are also considered.     

A phase I, randomized study of combined IL-2 and therapeutic immunisation with antiretroviral therapy

Background  

Fully functional HIV-1-specific CD8 and CD4 effector T-cell responses are vital to the containment of viral activity and disease progression. These responses are lacking in HIV-1-infected patients with progressive disease. We attempted to augment fully functional HIV-1-specific CD8 and CD4 effector T-cell responses in patients with advanced chronic HIV-1 infection.     

A theoretical investigation of the ground and core hole states of linear and bent NiCO; a prototype for CO adsorbed on nickel

Non-empirical LCAO MO SCF calculations within the Hartree-Fock formalism have been performed on linear and bent conformations of NiCO, for both the states arising from the 3d⁹4s¹ and 3d¹⁰ electronic configurations of Ni, for ground and core ionized species. Binding and relaxation energies are computed for the nickel atom, the free ligand (CO) and the absorbed species (NiCO). Comparison with available experimental data reveals good agreement for the shifts in core binding energies for the bent, 3d⁹4s¹ NiCO system. The main contribution to these binding energy shifts is found to be due to relaxation effects, which may be rationalized in terms of atomic population and bond overlap changes accompanying core ionization.     

A non-empirical LCAO MO SCF investigation of electronic relaxation accompanying core ionization in a series of saturated alkanes

Ab initio LCAO MO ΔSCF binding energies and relaxation energies have been computed at the STO-4.31G level for linear and branched alkanes (up to C₆) and are compared with experimental data. The structural dependence of binding energies and relaxation energies is discussed, and it is concluded that binding enegy shifts in these alkanes (compared with methane) arise mainly from relaxation energy changes.     

Femtosecond vibrational dynamics of self-trapping in a quasi-one-dimensional system

We have directly time resolved the lattice motions associated with the formation of the self-trapped exciton in the quasi-one-dimensional system [Pt(en)(2)] [Pt(en)2Br2];(PF6)(4) ( en = ethylene-diamine, C2H8N2), using femtosecond impulsive excitation techniques. A strongly damped, low-frequency wave packet modulation at approximately 110 cm(-1) accompanies the formation of the self-trapped exciton on a approximately 200 fs time scale following excitation of the intervalence charge-transfer transition. Coherent oscillations at the ground state vibrational frequency and its harmonics are also detected.