Hydration Enthalpies of Ba(2+)(H2O)x, x = 1-8: A Threshold Collision-Induced Dissociation and Computational Investigation.

The sequential bond dissociation energies (BDEs) of Ba(2+)(H2O)x complexes, where x = 1-8, are determined using threshold collision-induced dissociation (TCID) in a guided ion beam tandem mass spectrometer. The electrospray ionization source generates complexes ranging in size from x = 6 to x = 8 with smaller complexes, x = 1-5, formed by an in-source fragmentation technique. The only products observed result from sequential loss of water ligands.

Differentiation of microbial species and strains in coculture biofilms by multivariate analysis of laser desorption postionization mass spectra.

7.87 to 10.5 eV vacuum ultraviolet (VUV) photon energies were used in laser desorption postionization mass spectrometry (LDPI-MS) to analyze biofilms comprised of binary cultures of interacting microorganisms.

Threshold collision-induced dissociation and theoretical studies of hydrated Fe(II): binding energies and Coulombic barrier heights.

The first experimentally determined bond dissociation energies for losing water from Fe(2+)(H(2)O)(n) complexes, n = 4-11, are measured using threshold collision-induced dissociation (TCID) in a guided ion beam tandem mass spectrometer coupled to an electrospray ionization source that forms thermalized complexes. In this technique, absolute cross-sections for dissociation induced by collisions with Xe at systematically varied kinetic energies are obtained. After accounting for multiple collisions, kinetic shifts, and energy distributions, these cross-sections are analyzed to yield the energy thresholds for losing one, two, or three water ligands at 0 K.

Structural elucidation of biological and toxicological complexes: investigation of monomeric and dimeric complexes of histidine with multiply charged transition metal (Zn and Cd) cations using IR action spectroscopy.

The gas-phase structures of singly and doubly charged complexes involving transition metal cations, Zn and Cd, bound to the amino acid histidine (His) as well as deprotonated His (His-H) are investigated using infrared multiple photon dissociation (IRMPD) spectroscopy utilizing light generated by a free electron laser. IRPMD spectra are measured for CdCl(+)(His), [Zn(His-H)](+), [Cd(His-H)](+), Zn(2+)(His)(2), and Cd(2+)(His)(2) in the 550-1800 cm(-1) range. These studies are complemented by quantum mechanical calculations of the predicted linear absorption spectra at the B3LYP/6-311+G(d,p) and B3LYP/Def2TZVP levels.