The application of laser electronic spectroscopy to small metal-containing molecules, composed of a single metal atom bound to a single molecular ligand, is reviewed. The focus is on recent studies performed using supersonic cooling and is illustrated by selected examples containing group 2 (Mg, Ca, Sr and Ba) or group 12 metals (Zn and Cd). The discussion emphasizes similarities and differences in the electronic structures of these molecules as deduced from their spectra and from supporting theoretical calculations.

Main group metal‐ligand interactions in small molecules: New insights from laser spectroscopy

Computational modeling of the SiH3+O2 reaction and silane combustion

Understanding the high energetic behavior of nano-energetic porous silicon

High-Resolution, Rotationally Resolved Electronic Spectroscopy of the MgNC Radical.

Self-ignition and flame propagation properties of silane combustion systems have been studied through computer simulations using a database of kinetic and thermodynamic information that is consistent with current understanding of the elementary processes These new inputs include the mechanism for chain branching through the SiH3 radical, rate constants for the reactions of HO2 with silane and its breakdown products, and the reaction of SiO with oxygen Over the entire temperature range, the simulations show two distinct mechanisms At low temperatures, the kinetics of SiH3 is controlling, whereas at high temperatures, SiH2 chemistry is of key importance The results demonstrate that the upper explosion limit and ignition at room temperature and 1 bar can be described by the same set of reactions With the new database, many of the experimental observations can be reproduced, and predictions are made regarding dependencies on process parameters These include the critical conditions for chain ignition, the dependence of the critical pressure on the ratio of silane and oxygen concentration, and the temperature dependence of the critical ratio of silane to oxygen concentration A scenario for low-temperature ignition is presented At high temperatures, the importance of condensation processes for accurate prediction of flame velocities is clear For very lean flames, the maximum reaction rate occurs at the lower temperature region of the flame zone

Numerical study of low- and high-temperature silane combustion

Potential energy surfaces for the ground and two low-lying electronically excited states of CaNC/CaCN, are calculated using the ab initio molecular orbital (MO) configuration interaction (CI) method. The absorption and emission spectra of the system are computed by performing time-dependent quantum dynamical calculations on these surfaces. The most stable geometries for the two lowest lying 12Σ+ and 12Π electronic states correspond to the calcium isocyanide (CaNC) structure. These two states are characterized by ionic bonding and the potential energy curves along the bending coordinate are relatively isotropic. The result of our wave packet dynamics shows that the characteristics of the experimental spectra observed by the laser-induced fluorescence spectroscopy can be explained by the Renner–Teller splitting.

Theoretical study of the potential energy surfaces and dynamics of CaNC/CaCN

Ab initio G-2 calculations have been carried out for a number of elementary reactions relevant to low-temperature silane oxidation. The calculations have been made to identify the chain-branching process which enables the spontaneous ignition of silane at room temperature. Extensive calculations have also been made for the reactions of major intermediates with hydrogen atoms and water vapor.

Ab Initio Energetic Calculations of Elementary Reactions Relevant to Low-Temperature Silane Oxidation by Gaussian-2 Theory

Ab initio calculations have been carried out for the PH2 + O2 reaction by using Gaussian-2 theory, which is considered a key reaction to understand low-temperature phosphine combustion. It has been...

Ab Initio Study of PH2 + O2 Reaction by Gaussian-2 Theory

To elucidate the ionization dynamics, in particular the vibrational distribution, of H2O+(A) produced by photoionization and the Penning ionization of H2O and D2O with He*(2 3S) atoms, Franck–Condon factors (FCFs) were given for the ionization, and the transition probabilities were presented for the emission. The FCFs were obtained by quantum vibrational calculations using the three-dimensional potential energy surfaces (PESs) of and electronic states. The global PESs were determined by the multi-reference configuration interaction calculations with the Davidson correction and the interpolant moving least squares method combined with the Shepard interpolation. The obtained FCFs exhibit that the state primarily populates the vibrational ground state, as its equilibrium geometry is almost equal to that of , while the bending mode (ν2) is strongly enhanced for the H2O+(A) state; the maximums in the population of H2O+ and D2O+ are approximately v2 = 11–12 and 15–17, respectively. These results are consistent with the distributions observed by photoelectron spectroscopy. Transition probabilities for the system of H2O+ and D2O+ show that the bending progressions consist primarily of the emission, with combination bands from the (1, v′2 = 4–8, 0) level being next most important.

THEORETICAL TRANSITION PROBABILITIES FOR THE $\tilde{A}^{2}A_{1} -\tilde{X}^{2}B_{1}$ SYSTEM OF H2O+ AND D2O+ AND RELATED FRANCK–CONDON FACTORS BASED ON GLOBAL POTENTIAL ENERGY SURFACES

Satoshi Minamino

Papers

Theoretical study of the potential energy surfaces and dynamics of CaNC/CaCN

Ab Initio Energetic Calculations of Elementary Reactions Relevant to Low-Temperature Silane Oxidation by Gaussian-2 Theory

Ab Initio Study of PH2 + O2 Reaction by Gaussian-2 Theory

THEORETICAL TRANSITION PROBABILITIES FOR THE $\tilde{A}^{2}A_{1} -\tilde{X}^{2}B_{1}$ SYSTEM OF H2O+ AND D2O+ AND RELATED FRANCK–CONDON FACTORS BASED ON GLOBAL POTENTIAL ENERGY SURFACES