This paper presents the results from extensive theoretical studies of the electronic structure for nitrous oxide. These studies have included the development of correlated ab initio MCSCF/CI wave functions for each of some 30 states, including MCSCF excited root/same symmetry calculations where necessary. Also, in the case of seven lower states, the potential energy hypersurfaces and dipole moment functions have been scanned using both MCSCF/CI and SCF wave functions. Vertical spectrum calculations are the most accurate and have been carried out at several levels of sophistication, including SCF, MCSCF, and MCSCF/CI correlation for DZ, DZ+diffuse, DZ+d, and DZ+d+diffuse one-electron bases. From all of these calculations the adiabatic excitation spectrum is established and the behavior of a number of states upon dissociation under C∞v and Cs symmetry is examined. Adiabatic correlation diagrams are then constructed to summarize many of the results and to relate them to the asymptotic spectra O(k sL) +N2 ( j sΛ) and NO( j sΛ) +N(k sL). In the light of the present work, optical and electron impact data are interpreted and assigned. It is found that each feature observed in the 4–8 eV region is supported by an electronic transition (s) allowed only under Cs symmetry. These features derive such intensity as they have in consequence of vibrational motion of the molecule in its normal, linear ground state. In distinct contrast, the features observed above 8 eV are shown to involve vertical excitations allowed under C∞v as well as Cs symmetry. Several of these transitions have not been assigned previously. For others, such as the all important D1 Σ+ state, the present results provide the necessary hard evidence for making an assignment. Also reported are correlated ab initio, DZ+d treatments for the C2v isomer 1 1A1 (1 1A′) of normal nitrous oxide, and for the O–N2 van der Waals interaction. The 1 1A1, or ‘‘ring,’’ state is shown to be bound relative to O(1D)+N2 by some 1.2 eV. The O(3P)–N2 long range 1 3Π ab initio interaction potential is reasonably well fit by an exp-6 functional form V(r)=37.757 exp(−r/0.566 569)−47.139 r−6 in a.u.

As revolutionary as microelectronics has been as a technology, there are functions that it does not address. Microelectronics focuses on ever-smaller integrated circuits (ICs) in ever-fewer square millimeters of space to increase clock speeds and decrease the power required for computer processing functions. However, applications requiring control, communications, computing, and sensing over a large area are difficult or costprohibitive to achieve because of the material incompatibilities of traditional ICs with structures, materials, and manufacturing technology. Macroelectronics addresses these applications with the aim of providing active control circuitry in situ over areas of many square meters for displays, solar panels, x-ray imagers, surface measurements, structural shape control, vehicle health monitoring, and other large-system applications. The materials challenges of macroelectronics integrated circuits (MEICs) reviewed in this issue include lightweight flexible substrates, thin-film transistors (TFTs) with IC or near-IC performance, modeling, and manufacturing technology. Compatible component materials, flexible substrates, processing conditions, host system composition, and functionality provide grand challenges that are just beginning to be addressed by researchers.

The ground state potential energy surface of the nitrous oxide negative ion is characterized and related to that of the neutral molecule by a synergetic theoretical–experimental approach. Ab initio multiconfiguration self-consistent-field/configuration interaction (MCSCF/CI) and other calculations for N2O−(X 2A′) yield the minimum energy geometry (ReNN, ReNO, AeNNO) = (1.222±0.05 Å, 1.375±0.10 Å, 132.7±2°), the vibrational frequencies (ν1,ν2,ν3) = (912±100 cm−1, 555±100 cm−1, 1666±100 cm−1), the dipole moment μ =2.42±0.3 D, and other properties. The N2O− molecular ion in the X 2A′ state is found to have a compact electronic wavefunction—one with very little diffuse character. The MCSCF/CI bending potential energy curve from 70° to 180° for the X 1Σ+(1 1A′) state of N2O as well as the bending curve for the X 2A′ state of N2O− are also reported. The dissociation energy D (N2–O−) =0.43±0.1 eV and, thus, the adiabatic electron affinity E.A.(N2O) =0.22±0.1 eV and the dissociation energy D (N–NO−) =5.1±0.1 eV are determined from beam–collision chamber experiments. Corrections are made for both the dispersion in the ion beam and the translational motion of each target gas. The combined theoretical and experimental results yield a vertical electron affinity V.E.A.(N2O) of −2.23±0.2 eV and enable the construction of angular dependent Morse functions to represent the neutral and ionic surfaces. This construction leads to the determination of the minimum intersection locus as (V*, R*NN, R*NO, A*NNO) = (0.67±0.1 eV, 1.18±0.05 Å, 1.28±0.10 Å, 154±3°). The predicted activation energy of this critical point with respect to the asymptote O−, N2—0.21±0.1 eV—and the position of the critical point with R*NN well outside of the N2 (v=0) outer turning point imply that the reaction O−+N2→N2O+e will be strongly facilitated by reagent vibrational excitation.

The authors makes a discussion of the radiative mechanism for the production of H2+ from thermal He++H2 collisions.(AIP)

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