1309-48-4Relevant articles and documents
Microwave spectroscopy of MgO in the a3Π and X1Σ states
Kagi,Kawaguchi
, p. 179 - 184 (2006)
Pure rotational transitions of MgO in the a3Πi state and the ground X1Σ+ state (v=1-3) were observed in the 210-400 GHz region. The MgO molecule was produced by a DC discharge in a mixture of Mg vapor and N2O. A simultaneous deperturbation analysis for the X1Σ+, a3Π, and A1Π states was carried out for the observed transition frequencies including previous high-resolution data, where the energy levels were calculated by diagonalizing the energy matrix including the spin-orbit and orbit-rotation interactions among three electronic states with vibrational levels up to v=9. A centrifugal term of the spin-orbit interaction between the a3Πi and X1Σ+ states was newly introduced to improve quality of the fitting, to explain the observed Λ-type doubling of the a3Πi state.
Spectroscopic characterization of the F1Π1 'Rydberg' state of the MgO molecule
Bellert,Burns, Katherine L.,Van-Oanh, Nguyen-Thi,Wang, Jinjin,Breckenridge
, p. 725 - 728 (2003)
The F1Π1 'Rydberg' state of 24Mg 16O has been characterized by two-color Resonance-Enhanced Two-Photon Ionization (R2PI) spectroscopy in the 37000-39000 cm-1 region. Several rotationally resolved band
Dehydration of the sorel cement phase 3Mg(OH)2·MgCl 2·8H2O studied by in situ synchrotron X-ray powder diffraction and thermal analyses
Runcevski, Tomce,Dinnebier, Robert E.,Freyer, Daniela
, p. 100 - 105 (2014)
Dehydration is an important process which affects the chemical, physical and mechanical properties of materials. This article describes the thermal dehydration and decomposition of the Sorel cement phase 3Mg(OH) 2·MgCl2·8H2O, studied by in situ synchrotron X-ray powder diffraction and thermal analyses. Attention is paid on the determination of the chemical composition and crystal structure of the lower hydrates, identified as the phases 3Mg(OH)2·MgCl 2·5.4H2O and 3Mg(OH)2·MgCl 2·4.6H2O. The crystal structure of 3Mg(OH) 2·MgCl2·4.6H2O is solved and refined by the Rietveld method and a structural model for the 3Mg(OH) 2·MgCl2·5.4H2O phase is given. These phases show statistical distribution of water molecules, hydroxide and chloride anions positioned as ligands on the magnesium octahedra. A structural scheme of the temperature induced transformations in the thermal range from 25 to 500 °C is presented.
A new model for magnesium chemistry in the upper atmosphere
Plane, John M. C.,Whalley, Charlotte L.
, p. 6240 - 6252 (2012)
This paper describes the kinetic study of a number of gas-phase reactions involving neutral Mg-containing species, which are important for the chemistry of meteor-ablated magnesium in the upper mesosphere/lower thermosphere region. The study is motivated by the very recent observation of the global atomic Mg layer around 90 km, using satellite-born UV-visible spectroscopy. In the laboratory, Mg atoms were produced thermally in the upstream section of a fast flow tube and then converted to the molecular species MgO, MgO2, OMgO2, and MgCO3 by the addition of appropriate reagents. Atomic O was added further downstream, and Mg was detected at the downstream end of the flow tube by laser-induced fluorescence. The following rate coefficients were determined at 300 K: k(MgO + O → Mg + O2) = (6.2 ± 1.1) × 10-10; k(MgO2 + O → MgO + O2) = (8.4 ± 2.8) × 10-11; k(MgCO3 + O → MgO2 + CO2) ≥ 4.9 × 10-12; and k(MgO + CO → Mg + CO2) = (1.1 ± 0.3) × 10-11 cm3 molecule-1 s-1. Electronic structure calculations of the relevant potential energy surfaces combined with RRKM theory were performed to interpret the experimental results and also to explore the likely reaction pathways that convert MgCO3 and OMgO2 into long-lived reservoir species such as Mg(OH)2. Although no reaction was observed in the laboratory between OMgO2 and O, this is most likely due to the rapid recombination of O2 with the product MgO 2 to form the relatively stable O2MgO2. Indeed, one significant finding is the role of O2 in the mesosphere, where it initiates holding cycles by recombining with radical species such as MgO 2 and MgOH. A new atmospheric model was then constructed which combines these results together with recent work on magnesium ion-molecule chemistry. The model is able to reproduce satisfactorily some of the key features of the Mg and Mg+ layers, including the heights of the layers, the seasonal variations of their column abundances, and the unusually large Mg+/Mg ratio.
High resolution spectroscopy of MgOH (X 2Σ+) in its V2 mode: Further evidence for quasilinearity
Apponi,Anderson,Ziurys
, p. 10919 - 10925 (1999)
Pure rotational spectra of the MgOH and MgOD radicals have been recorded in the v2 bending vibration of their X 2Σ+ ground electronic states using millimeter-wave direct absorption spectroscopy. Multiple rotational transitions arising from the v12= 11, 22, 20, 31, 33, 42, and 44 substates have been measured in the frequency range 240-520 GHz for these species. Both the spin-rotation and l-type doubling interactions have been resolved in the spectra. The complete data sets for MgOH and MgOD have been analyzed using a linear model for the Hamiltonian which takes into account higher order (l=±4) l-type interactions. The global analyses were adequate, but anomalous behavior was apparent in both molecules. In particular, the Bv vs v2 relation was found to be highly nonlinear, large variations in the l-type doubling constant q were observed with vibrational level, and r0, rs, and re structures determined differed substantially. Such findings suggest that MgOH is highly quasilinear, comparable to HNCO. The competition between ionic and covalent bonding is therefore becoming apparent in the lighter alkaline earth hydroxide species.
Laser spectroscopic studies of several Rydberg states of MgO
Wang, Jinjin,Breckenridge, W. H.
, p. 1 - 6 (2008/10/09)
We report extensive spectroscopic measurements of rovibronic transitionsfrom the MgO X 1∑+ ground state to the high-e nergy E 1∑+, F Π11, and G Π11 Rydberg states. Perturbations in the E 1∑+ and G Π11 states were observed. The Rydberg molecular orbital character of the three states is examined, given ab initio calculations by Thummel [Chem. Phys. 129, 417 (1989)]. It is concluded that the E 1∑+ and G Π11 states consist primarily of the Mg O+ X Π2 ionic core, surrounded by 3p? and 3p? Rydberg electron clouds, respectively, and that the F Π11 state consists primarily of the Mg O+ A 2∑+ ionic core surrounded by a 3p? Rydberg electron cloud. Spectroscopic characterizations of some unassigned vibrational levels of analogous MgO Π23 states in this energy region are also reported.
