Further studies of the electronic and vibrational spectra of ND2: Improved molecular parameters for the 000 and 010 levels of the ground state

Improved molecular parameters for the 000 and 010 levels of the $\text{X}\text{?}{}^2\text{B}{}_1$ ground state of ND₂ have been obtained by a weighted least-squares treatment using published microwave-optical double resonance frequencies, laser magnetic resonance data, infrared-optical double resonance frequencies, and extensive new optical data for the $\text{A}\text{?}{}^2\text{A}{}_1\text{-}\text{X}\text{?}{}^2\text{B}{}_1$ absorption spectrum. Revised assignments are given for 13 LMR transitions, including 4 “hot” band transitions.     

Singlet-triplet perturbations in formaldehyde

The magnetic rotation spectrum of formaldehyde in the region of 3260 Å has been studied under high resolution using magnetic flux densities ranging from 80–5000 G. Approximately 40 magnetically sensitive rotational levels have been identified. Matrix elements and possible mechanisms are discussed.     

Ultraviolet absorption spectrum of Cr2O3 from reflectivity measurements

Reflectivity measurements have been made on Cr₂O₃ single crystals in the energy range 1.2 eV to 20.0 eV. The results, which include three absorption peaks not previously reported, have been analysed both in terms of the crystal splitting of energy levels of the Cr³⁺ ion and of charge transfer.     

Synthesis of bimodal mesoporous Ni oxide from octylamine

Mesoporous Ni hydroxynitrates were synthesized from a hydrothermal mixture of Ni nitrate, octylamine as the surfactant, ethanol and water at 25–100 °C for 24 h. Mesoporous Ni oxides were obtained by calcining the Ni hydroxynitrates in air at temperatures ranging from 200 to 500 °C for 2 h. The mesoporous Ni oxides have crystalline walls, a high surface area of 133 m²/g at 350 °C, high porosity up to 0.61 cm³/g, and a bimodal mesopore size distribution, with pores roughly 2 and 10–25 nm in diameter. With an increase in the synthesis temperature, the size of the larger pores and the total pore volume of the mesoporous Ni oxide increase, while the surface area decreases slightly from 133 (25 °C) to 111 m²/g (100 °C).     

Multivector analysis II: A comparison with vector algebra

In a companion paper (I) it is shown that a comparison of the procedures used in tensor analysis to accommodate physical tensors with those appropriate to multivector analysis leads, in effect, to the replacement of two tensor species by 18 (in tensor analysis). In order to make tensor analysis work in practice, this divergence must be removed and this can be done, as is explained in detail, by imposing a sequence of constraints. There is then a convergence to a situation in which two tensor species suffice, corresponding to the polar and axial vector.     

Impact of porous electrode properties on the electrochemical transfer coefficient

The rate of an activation-controlled electrochemical reaction is determined by two key parameters, the exchange current density, io, and the transfer coefficient, alpha, which is inversely related to the Tafel slope. Assuming that the symmetry factor, beta, is 0.5, the minimum alpha value should be 0.5 for all standard reaction mechanisms, with alpha values larger than this indicating a better electrocatalytic mechanism. The primary goal of this paper is to better understand why alpha values of < 0.5 are often observed experimentally, with specific examples given for the oxygen reduction reaction. These low alpha values cannot be explained by adsorption behavior, but they can result when reactions occur within a porous electrode structure. Consistent with past literature related to Tafel slope predictions, we show that long and narrow pores, a low ionic or electronic conductivity of the electrode layer, and a high io value can cause alpha to be < 0.5, most typically 0.25. However, alpha values between 0.25 and 0.5 are also encountered in practice. We show here that such alpha values can be obtained for reactions occurring at porous films that have nonuniform properties. We also show that the overpotential range over which alpha changes from 0.5 to 0.25 can be quite broad, especially at high temperatures, and thus can be misinterpreted as a true Tafel region with a transfer coefficient between 0.25 and 0.5.     

Structural characteristics of different types of nanoparticles synthesised in mesomorphic metal alkanoates

The class of thermotropic ionic liquid crystals (LCs) of the metal alkanoates possesses a number of unique properties, such as intrinsic ionic conductivity, high dissolving ability and ability to form time-stable mesomorphic glasses. These ionic LCs can be used as nanoreactors for the synthesis and stabilisation of different types of nanoparticles (NPs). Thus, some semiconductors, metals and core/shell NPs were chemically synthesised in the thermotropic ionic liquid crystalline phase (smectic A) of the cadmium octanoate (CdC₈) and of the cobalt octanoate (CoC₈). By applying the scanning electron microscopy, the cadmium and cobalt octanoate composites containing CdS, Au, Ag and core/shell Au/CdS NPs have been studied. NPs’ sizes and dispersion distribution of the NPs’ size in the nanocomposites have been obtained.     

Synthesis and characterization of alkoxide-derived pt nanoparticles

Identification of the species formed during the in situ reduction of hexachloroplatinic acid by sodium ethoxide, forming a Pt sol, is made. The solution phase is shown to consist of suspended metallic Pt nanoparticles (1-3 nm in diameter), acetaldehyde, and a Pt(II) species, identified by NMR and X-ray adsorption near-edge spectroscopy (XANES) to be NaPtCl3(C2H4), a sodium analogue of Zeise's salt [KPtCl3(C2H4)]. The NaPtCl3(C2H4) product exhibits greater stability in both ethanol and air than the conventional Zeise's salt, providing a means of storing the useful Zeise's anion [PtCl3(C2H4)-]. Electrochemistry, X-ray diffraction (XRD), and transmission electron microscopy (TEM) analyses have shown that the precipitate phase formed during the synthesis is composed solely of Pt particles approximately 6 nm in diameter and NaCl. Thermal gravimetric analysis/differential scanning calorimetry (TGA/DSC) showed that the color of the precipitate is an accurate gauge of the ratio of Pt to NaCl, with the lightest to darkest precipitates containing from 1% to 40% nanoparticulate Pt by mass, respectively. A comprehensive characterization of both phases formed has allowed us to propose a mechanism for the conversion of hexachloroplatinic acid to Pt nanoparticles.