A simple wavefunction containing two variational parameters is shown to yield accurate energies of two-electron atoms. In contrast to previous analogous treatments the present method proves not only successful for S states, but also gives accurate results for P and D states.

Quantitative data on the in‐plane anisotropy of charge transportin an aligned polyfluorene (PF) film can be obtained thanks to the technique described in this communication (see Figure for principle). Since the method revealed here does not require the deposition of electrode layers, it can be more readily applied to the characterization of a large number and variety of structured, thin‐layer samples, free of the complications that often accompany DC measurements.

A simple configuration interaction method to calculate accurate electronic energies of two-electron molecules at intermediate internuclear distances is presented. The correlated basis functions are constructed from H2+ molecular orbitals (exact solution of the two-centre Coulombic problem), and include an explicit dependence on the interelectronic distance in order to describe the major part of the electronic correlation. The first Green transformation is used to give an important simplification of the expression for the matrix elements of the Hamiltonian. The method is shown to give accurate energies for the H2 molecule in the ground 1 Sigma g state at intermediate distances, and is applied to determine new potential curves of highly excited states. The simplicity of the wavefunction will allow it to be used relatively easily in subsequent calculations of dynamical properties.

Nonadiabatic calculations have been performed for the g, h, i, and j states of H2, HD, and D2, yielding the lowest rovibrational levels (v, lV =0, 1,2, 3). Born-Oppenheimer potential-energy curves were taken from literature. Irregularly shaped rotational and vibrational couplings were significantly reduced by an appropriate electronic basis transformation.In the diabatic electronic basis introduced here the rotational matrix elements were fixed to their united-atom-limit values, and the vibrational matrix elements were adjusted to reproduce experimental data. Apart from the hydrogen h X~s tate v=2 and 3 series that we suspect are misassigned, we obtained agreement with experiment down to a wave number for all calculated energy levels. Calculated branching ratios for radiative decay, which are very sensitive to the excited-state electronic composition, are found to agree with experimental data [following paper, Phys. Rev. A 44, 4171 (1991)].The confusion in the nomenclature of the adiabatic electronic 'X+ states is addressed.PACS number(s): 33.10.Lb

Resonances in the differential photodissociation cross section of H2 are studied. Photon excitation from the metastable c II"state occurs around resonances in the j hg state lying in the continuum of the i II~state. The j hg state is coupled to the continuum by the nuclear rotation. Since direct excitation to the continuum can also occur, interference is present, which expresses itself as a change in anisotropy of the photofragments as the photon energy is scanned over a resonance. Fano parameters, linewidths, and anisotropy parameters are obtained from the measured differential cross sections and are treated theoretically as outlined in the preceding paper Siebbeles, Phys. Rev. A 44, 1577 (1991)]. The experimental and calculated results are in good agreement.