Unimolecular reaction systems in which multiple isomers undergo simultaneous reactions via multiple decomposition reactions and multiple isomerization reactions are of fundamental interest in chemical kinetics. The computer program suite described here can be used to treat such coupled systems, including the effects of collisional energy transfer (weak collisions). The program suite consists of MultiWell, which solves the internal energy master equation for complex unimolecular reactions systems; DenSum, which calculates sums and densities of states by an exact-count method; MomInert, which calculates external principal moments of inertia and internal rotation reduced moments of inertia; and Thermo, which calculates equilibrium constants and other thermodynamics quantities. MultiWell utilizes a hybrid master equation approach, which performs like an energy-grained master equation at low energies and a continuum master equation in the vibrational quasicontinuum. An adap- tation of Gillespie's exact stochastic method is used for the solution. The codes are designed for ease of use. Details are presented of various methods for treating weak collisions with virtually any desired collision step-size distribution and for utilizing RRKM theory for specific unimolecular rate constants. 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 232- 245, 2001

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Multiple‐Well, multiple‐path unimolecular reaction systems. I. MultiWell computer program suite

Synthesis and Applications

Thermochemical determinations by the kinetic method

Properties and Synthetic Utility of N-Substituted Benzotriazoles.

C(NHC)2: divalent carbon(0) compounds with N-heterocyclic carbene ligands-theoretical evidence for a class of molecules with promising chemical properties.

A conventional double focusing mass spectrometer has been modified in order to obtain mass-analyzed ion kinetic energy spectra.

Mass Analyzed Ion Kinetic Energy Spectrometry with a Modified AEI MS 902 Spectrometer

Ethynamine (HO≡CNH) has been prepared from three different precursors (7a, 7b, and 8) by flash vacuum pyrolysis and observed by low-temperature infrared spectroscopy for the first time. The collision activation mass spectra (CAMS) strongly support the assignments. The Meldrum's acid derivative 8 also gives rise to equilibrating imidoylketene (10) and aminopropadienone (9), observable by both IR and CAMS. 9 decarbonylates above 680 °C to ethynamine. Ethynamine isomerizes in part to acetonitrile in the gas phase but polymerizes in the solid state between-70 and-50 °C. Both ketene imine (HC═C═NH) and acrylonitrile are formed on FVP of 3-hydroxypropionitrile. 2-Phenylethynamine (PhC≡CNH) is readily produced by FVP of the isoxazolone 11.

Primary ethynamines (HC≡CNH2, PhC≡CNH2), aminopropadienone (H2NCH=C=C=O), and imidoylketene (HN=CHCH=C=O). Preparation and identification of molecules of cosmochemical interest

2,5-Dithiacyclopentylideneketene (4) is obtained by flash vacuum pyrolysis (FVP) of the Meldrum's acid derivative 1 and characterized by MS, IR, and NMR spectroscopy. 4 is stable in solution at -50-degrees-C. FVP of 4 as well as the isoxazolone derivatives 2 and 3 results in efficient cleavage into ethylene and ethenedithione, S=C=C=S, which is remarkably stable in the gas phase at high temperature, low pressure, and short contact times but extremely unstable in the condensed state or at higher pressures.

2,5-Dithiacyclopentylideneketene and Ethenedithione, S=C=C=S, Generated by Flash Vacuum Pyrolysis

Contaminant levels in sediments and asteroids (Asterias rubens L., Echinodermata) from the Belgian coast and Scheldt estuary: polychlorinated biphenyls and heavy metals.

Protonated 4-bromophenol and 4-bromoanisole produced by methane chemical ionization are found to easily be dehalogenated upon high (8 keV) or low (20−30 eV) energy collisional activation giving ess...

Robert Flammang

Papers

Mass Analyzed Ion Kinetic Energy Spectrometry with a Modified AEI MS 902 Spectrometer

Primary ethynamines (HC≡CNH2, PhC≡CNH2), aminopropadienone (H2NCH=C=C=O), and imidoylketene (HN=CHCH=C=O). Preparation and identification of molecules of cosmochemical interest

2,5-Dithiacyclopentylideneketene and Ethenedithione, S=C=C=S, Generated by Flash Vacuum Pyrolysis

Contaminant levels in sediments and asteroids (Asterias rubens L., Echinodermata) from the Belgian coast and Scheldt estuary: polychlorinated biphenyls and heavy metals.

Ionized Phenol and Its Isomers in the Gas Phase