M. Barber

Fast atom bombardment: A new mass spectrometric method for peptide sequence analysis

Abstract We have studied a selection of peptides using a new mass spectrometric ionisation technique - fast atom bombardment (FAB). We define the fragmentation pathways observed and comment on the utility in sequence analysis. A simple acetylation experiment is shown to aid rapid sequence assignment.

Fast atom bombardment of solids (F.A.B.): a new ion source for mass spectrometry

A new method for obtaining high-quality mass spectra of molecules which previously were difficult or impossible to study by ionisation methods is described

On the bonding of the ions PO4 3-, SO4 2-, ClO4 -, ClO3 - and CO3 2- as studied by X-ray spectroscopy and ab initio SCF-MO calculations

The ionization energies of the valence electrons of the ions PO4 3-, SO4 2-, ClO4 -, ClO3 - and CO3 2- are measured by X-ray photoelectron spectroscopy. An assignment of the spectra is made using the results of all electron ab initio SCF-MO calculations, reported here, together with X-ray emission spectra from the literature. The calculated atomic orbital composition of the molecular orbitals allows the intensities of the X-ray spectra to be understood, and provides further evidence for d-orbital participation in the bonding of the second row atoms.

Bonding in some donor–acceptor complexes involving boron trifluoride. Study by means of ESCA and molecular orbital calculations

Core binding energies of a number of nitrogen bases and their adducts with BF3 are reported, and interpreted using both ab initio and semi-empirical molecular orbital calculations. The binding energies are found to reflect the change in molecular charge distribution which occurs on formation of the B—N σ bond. The correlation of the valence molecular orbitals of the complexes with those of the bases and BF3 is discussed.

On the Electronic Structure of Some Nitrogen‐Containing Molecules as Studied by Ab Initio SCF MO Calculations and High‐Energy Electron Spectroscopy

Nitrogen 1s binding energies in HN3 and the potassium salts of NO2−, NO3−, and N3− are measured and interpreted in terms of ab initio SCF MO calculations. The valence orbitals must be represented by a double‐zeta basis of STOs to adequately interpret the chemical shifts. Inclusion of the lattice potential in the case of the ionic compounds allows a good correlation between calculated and experimental 1s binding energies to be obtained for both ionic and nonionic compounds.

On the origin of satellite peaks in the high energy photoelectron spectra of some transition metal carbonyls

Abstract Satellite peaks in the high energy photoelectron spectra of a number of transition metals are reported, and their origin is suggested as arising from the poor description of the ground states of these molecules in the Hartree-Fock limit.

Ab initio molecular orbital calculations of transition metal complexes: III. The ground states of the permanganate, chromate and vanadate ions as studied by extended basis SCF-MO calculations and X-ray spectroscopy

The electronic structure of the ground states of the permanganate, chromate and vanadate ions are studied by ab initio SCF-MO calculations in a near double-zeta basis. The X-ray emission spectra of these ions are interpreted with the aid of the calculations, which, together with their X-ray photoelectron spectra reported here, allows an ordering of the molecular orbitals to be deduced.

The application of SIMS to the study of CO adsorption on polycrystalline metal surfaces

Abstract Secondary ion mass spectroscopy (SIMS) was used to study the adsorption of carbon monoxide on polycrystalline nickel, copper, iron, palladium and tungsten foils. The results demonstrate the ability of SIMS to distinguish, qualitatively, between molecular and dissociative adsorption. A correlation between SIMS results and those obtained by infra-red spectroscopy for molecular adsorption is also suggested.

Fast atom bombardment mass spectrometry of human proinsulin

Abstract The observation of protonated molecular species from human proinsulin obtained by fast atom bombardment mass spectrometry is reported.

Fast atom bombardment mass spectrometry of bleomycin A2 and B2 and their metal complexes.

Abstract The new mass spectrometric technique of fast atom bombardment is applied to the analysis of bleomycins either separately or in mixtures. The spectra are reproducible and afford valuable analytical data and structurally significant fragmentation patterns on these important antibiotics. The procedures outlined have also enabled the characterisation of various metal complexes.