Quadrupolar coupling constants of 170 kHz result from reduced motional averaging in biological polymers. The decay rates of Zeeman and quadrupolar order are direct measures of the spectral densities of motion. Information on the orientation-dependence of relaxation rates of Zeeman and quadrupolar order, Tlz and Tlq respectively, assists in understanding the dynamics of molecules. Sensitivity an...

Transient network hydrogels cross-linked through histidine-divalent cation coordination bonds were studied by conventional rheologic methods using histidine-modified star poly(ethylene glycol) (PEG) polymers. These materials were inspired by the mussel, which is thought to use histidine-metal coordination bonds to impart self-healing properties in the mussel byssal thread. Hydrogel viscoelastic...

Ion–molecule reactions between neutral methyl formate (MF) and proton-bound solvent clusters W2H+, W3H+, M2H+, E2H+, E3H+ (W = water, M methanol, E ethanol) showed that the major reaction product is a molecule loss from initial encounter complex, followed by formation of protonated (MFH+). Collision-induced dissociation breakdown curves initially formed solvent-MF pairs trimers were obtained as...

We review the results of our recent experimental and theoretical studies gas-phase ion-molecule reactions involving He+ ion at low collision energies (Ecoll), in kB⋅(0 – 40) K range. To avoid heating ions by stray electric fields, are studied within orbit a Rydberg electron. reach down to ~0 employing merged-beam setup. In case molecule with dipole moment (e.g., ammonia), we observe strong enha...

The influence of the surroundings on the linear dipole polarizability a and second hyperpolarizability 7 is discussed in terms of the density om of isotropically distributed matter as well as the density qp of thermal black-body radiation photons, a and 7 of the rare gas atoms are studied as examples. At standard conditions, both effects are of comparable size for the rare gases. Possible conse...

A pending issue in linking ion mobility measurements to ion structures is that the collisional cross section (CCS, the measured structural parameter in ion mobility spectrometry) of an ion is strongly dependent upon the manner in which gas molecules effectively impinge on and are reemitted from ion surfaces (when modeling ions as fixed structures). To directly examine the gas molecule impingeme...

Ozone-induced dissociation (OzID) is an alternative ion activation method that relies on the gas phase ion-molecule reaction between a mass-selected target ion and ozone in an ion trap mass spectrometer. Herein, we evaluated the performance of OzID for both the structural elucidation and selective detection of conjugated carbon-carbon double bond motifs within lipids. The relative reactivity tr...

A series of six L-amino acid hydrochloride salts has been studied by 35/37Cl solid-state NMR spectroscopy (at 11.75 and 21.1 T) and complementary quantum chemical calculations. Analyses of NMR spectra acquired under static and magic-angle-spinning conditions for the six hydrochloride salts, those of aspartic acid, alanine, cysteine, histidine, methionine and threonine, allowed the extraction of...