Narrow Results

The surface electrochemical response of the Co^II/Co^I redox process of tetraaminophthalocyaninatocobalt(II) (Co^IITAPc) adsorbed on a graphite electrode, was studied in the pH range of 2–13. In aqueous solution, the Co^IITAPc adsorbed graphite electrode displays very strong electrocatalytic activity toward N₂O reduction to N₂, a process which was examined by cyclic and rotating disk electrode voltammetries. The possible application of this Co^IITAPc modified electrode in N₂O analysis was explored.

In this paper, we study single and double ionizations of N₂O in a short elliptically polarized 800 nm laser pulse using the COLTRIMS technique. The molecular-frame photoelectron angular distribution and the ion sum-momentum distribution of single and double ionizations of N₂O molecules are reported for the single ionization dissociative channel NO${}^{+}$ + N and the double ionization dissociative channel NO${}^{+}$ + N${}^{+}$. The ionizations of multiple orbitals for the two studied dissociative channels were identified via studying the orientation dependent ionization rates for their KERs. The results show that the shape of the ionizing orbitals governs the single and double ionization processes of N₂O.

The emissions of nitric oxide and carbon monoxide from internal combustion engines generate a large impact on the environment and on people's health. Catalytic reduction of these species using platinum group metals has already shown significant potential for emissions control. Since catalysts often use carbon monoxide to reduce nitric oxide in these devices, accurate models of their interaction are required to advance catalyst simulations in order to meet increasingly stringent emissions regulations. As a result, this paper reviews the literature of the NO–CO reaction over platinum in order to develop more precise detailed and global reaction mechanisms for use in exhaust after-treatment modeling activities. Moreover, it is found that the reaction between NO and CO over platinum yields carbon dioxide and nitrogen as main products and nitrous oxide as an important side product. Hence, this paper additionally describes the mechanism for nitrous oxide production in advance of greenhouse gas regulations.

Theoretical calculations 6-311++G(d,p) have been performed in order to obtain binding energies and molecular properties of complexes involving nitrous oxide (N₂O) and two HX (X = F, Cl, Br and CN) molecules. Our calculations have revealed the existence of eleven stable structures. The vibrational changes which take place in the HX acid after complexation follow the usual behavior: the HX stretching frequency is shifted downward whereas its IR intensity is much enhanced. The new vibrational modes arising upon H-bond formation, were verified, especially, those associated with the out-of-plane and in-plane HX bending modes, which are pure rotations in the HX isolated molecule.

A great deal of theoretical work has been carried out to investigate the properties of the six lowest singlet electronic states of N₂O molecule: the ground state X¹A′; the excited states 1¹A′′, 2¹A′, 2¹A′′, 3¹A′ and 3¹A′′. Multireference configuration interaction (MRCI) approach has been used to compute the full-dimensional potential energy surfaces of the six lowest states employing aug-cc-pVQZ minus g orbital basis set. It was found that such of highly accurate potential yields excellent results of bond dissociation and vertical excitation energies in comparison with the experimental values. Several important symmetry and nonsymmetry related conical intersections in linear and bent geometries have been discussed. Of particular interest is the location of conical intersections between the 2¹A′(¹Δ) and 3¹A′(¹Π) states, and between the 1¹A′′(¹Σ^-) and 3¹A′′(¹Π) states in linear geometry, as well as conical intersection between the X¹A′ and 2¹A′ states in bent geometry. The corresponding transition dipole moment surfaces have also been computed, connecting the ground electronic state to the lowest five excited states. Detailed discussion on the vector properties of the dipole transition has been presented specifically in the vicinity of the conical intersections.

The electrocatalytic reduction of nitrite on a dinuclear ruthenium phthalocyanine (RuPc)₂ modified electrode is studied, using cyclic voltammetry (cyclic voltammogram), rotating disc electrode (RDE) and ring-disc electrode (RRDE) techniques. The products of nitrite reduction are ammonia, nitrous oxide, and hydroxylamine. Depending on the experimental conditions, ammonia or nitrous oxide is formed as the main product. The initial step in the electroreduction of nitrite catalyzed by (RuPc)₂ is a one electron Ru^II / Ru^I process, followed by coordination of NO₂⁻ to the metal center. Formation of a nitrosyl complex prior to the electroreduction does not occur. A suitable mechanism is proposed by analyzing the rate equation and the Tafel slope.

The lifetime of the asymmetric fundamental stretching 2218 cm^-1 vibration of the anesthetic gas nitrous oxide (N₂O) dissolved in octanol and olive oil is reported. These solvents are model systems commonly used to assess anesthetic potency. Picosecond time-scale molecular dynamics simulations have suggested that protein dynamics or membrane dynamics play a role in the molecular mechanism of anesthetic action. Ultrafast infrared spectroscopy with 100 fs time resolution is an ideal tool to probe dynamics of anesthetic molecules on such timescales. Pump-probe studies centered at the peak of the vibrational band yield a lifetime of 55 ± 1 ps in olive oil and 52 ± 1 ps in octanol. The similarity of lifetimes suggests that energy relaxation of the anesthetic is determined primarily by the hydrophobic nature of the environment, consistent with models of anesthetic action. The results show that nitrous oxide is a good model system for probing anesthetic-solvent interactions using nonlinear infrared spectroscopy.

Nitrous oxide in oxygen (N₂O/O₂) inhalation sedation is used less commonly by Singapore dentists than their counterparts in the United Kingdom and the United States. Using this technique, trained dentists often perform the dual roles of a sedationist and an operating dentist. This paper describes the mechanism of action of N₂O and highlights the modern gas delivery system commonly used in dentistry. The built-in safety features of this unique system helps to ensure that patient-specific therapeutic dosages are effectively and safely administered by dentists. Existing evidence for adverse events and the safety profile of the N₂O/O₂ inhalation sedation is discussed. Finally, recommendations of equipment, training and techniques for safe N₂O/O₂ inhalation sedation are provided.

Although agricultural production contributed about 10% of all greenhouse gas emissions in the United States in 2019, existing agricultural practices are capable of making the sector carbon neutral. Whether American agriculture will ultimately achieve carbon neutrality is ultimately a question of political will, not a scientific one. Given the right policy environment, farms and ranches will be able to cut their emissions and use their land to sequester carbon, while becoming more climate resilient, productive, and profitable…