We used dispersion-corrected density functional theory (DFT-D3) calculations to investigate the initial C-H bond cleavage of propane σ-complexes adsorbed on the PdO(101) surface. The calculations predict that propane molecules adsorbed in η(1) configurations can undergo facile C-H bond cleavage on PdO(101), where the energy barrier for C-H bond activation is lower than that for desorption for e...

Free radical-initiated peptide sequencing (FRIPS) mass spectrometry derives advantage from the introduction of highly selective low-energy dissociation pathways in target peptides. An acetyl radical, formed at the peptide N-terminus via collisional activation and subsequent dissociation of a covalently attached radical precursor, abstracts a hydrogen atom from diverse sites on the peptide, yiel...

We investigate hydrogen dissociation from an isolated Si-H bond in bulk silicon, using ab initio densityfunctional total-energy calculations. From the bonding site, we find that hydrogen needs to overcome a barrier of less than 2.0 eV in order to reach the next lowest local minimum in the energy surface. This minimum occurs at the antibonding site and is 1.2 eV higher in energy than the ground ...

Double bond locations in fatty acids can be determined from characteristic charge-remote fragmentation patterns of alkali metal-adducted fatty acids following high energy collision activated dissociation (CAD). With low energy CAD, several chemical derivatization methods, including ozonization, epoxidation, and hydroxylation, have been used to generate characteristic fragments. However, high en...

NO2 fission is a vital factor for 1,3,5-Trinitroperhydro-1,3,5-triazine (RDX) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) decomposition. In this study, the geometry of the gas-phase RDX and HMX molecules was optimized, and the bond order and the bond dissociation energy of the N-N bonds were examined. Moreover, the rate constants of the gas-phase RDX and HMX conformers, concernin...

Quantum chemical calculations of the structures and thermodynamics of homolytic dissociation of the central P-P and N-N bonds in tetrakis(disyl)diphosphine and tetrakis(di-tert-butylsilyl)hydrazine have been performed. The theory predicted negative standard enthalpies for homolytic bond dissociation in both cases, -71.0 and -108.4 kJ mol(-1) for the diphosphine and hydrazine, respectively, usin...

We summarize here our experimental studies of the high rovibrational energy levels of water. The use of double-resonance vibrational overtone excitation followed by energy-selective photofragmentation and laser-induced fluorescence detection of OH fragments allowed us to measure previously inaccessible rovibrational energies above the seventh OH-stretch overtone. Extension of the experimental a...

The gas-phase thermochemistry of actinide monosulfides, AnS, was investigated experimentally and theoretically. Fourier transform ion cyclotron resonance mass spectrometry was employed to study the reactivity of An(+) and AnO(+) (An = Th, Pa, U, Np, Pu, Am and Cm) with CS(2) and COS, as well as the reactivity of the produced AnS(+) with oxidants (COS, CO(2), CH(2)O and NO). From these experimen...

Side-chain/ring oxygenated product ratio increases upon decreasing the benzylic bond dissociation energy in oxidation of alkylaromatics with H2O2 catalyzed by an imine-based iron complex.

A triple-quadrupole mass spectrometer has been modified for bond-dissociation energy measurements via threshold collision-induced dissociations (TCIDs) by replacing the conventional collision cell with a ring ion guide. Optimal operating conditions for the ring ion guide were determined or derived, and validated using a set of complexes for which bond dissociation energies are known. A comparis...