نتایج جستجو برای: ion quadrupolar molecule collision rate constants
تعداد نتایج: 1338334 فیلتر نتایج به سال:
Residual dipolar couplings between spin-1/2 and quadrupolar nuclei are often observed and exploited in the magic-angle spinning (MAS) NMR spectra of spin-1/2 nuclei. These orientation-dependent splittings contain information on the dipolar interaction, which can be translated into structural information. The same type of splittings may also be observed for pairs of quadrupolar nuclei, although ...
In this paper we study the integrability properties of a general version of the Boltzmann collision operator that includes inelastic interactions between particles. We prove a Young’s inequality for variable hard potentials, a Hardy-Littlewood-Sobolev inequality for soft potentials, and estimates with Maxwellian weights for variable hard potentials. In addition we obtain sharp constants for Max...
Selected ion flow tube – mass spectrometry (SIFT-MS) is based on chemical reactivity of analytes with reactant ions. The complete understanding all the ion–molecule reactions key to deployment this technology for direct and rapid analysis VOCs in gas phase. In present work, we focused carboxylic acids esters, compounds involved many biochemical processes. negative precursor ions (OH–, O●−, O2●−...
The electronic energy transfer pathways that occur following collisions between I 2 in the E ion-pair electronic state ͑vϭ0, Jϭ55͒ and He and Ar atoms have been determined. The nearby D, DЈ, and  ion-pair states are populated, but with relative branching ratios that vary with the rare gas collision partner. In He/I 2 collisions, the D state is preferentially populated, while Ar/I 2 collisions pr...
Blocking: Reduction of detector signal rate when aligned with a crystal axis or plane. Channeling: Guided trajectory of incident ions between crystal axes or planes. Collision cascade: Series of atom-atom collisions initiated by an ion-atom collision. Cross section: Effective area presented by each atom or nucleus for a specific type of interaction with an incoming ion. lmplantation: Addition o...
Different alkali metal atoms are observed to donate electrons to CF(3)Br molecules that are oriented in space. For collision energies high enough to overcome the Coulomb attraction, a positive ion/negative ion pair is observed and mass-analyzed using coincident time-of-flight mass spectroscopy. The alkali metal cation and various negative ions are observed. The most abundant negative ion is the...
Surface-induced dissociation (SID) and collision-induced dissociation (CID) are ion activation techniques based on energetic collisions with a surface or gas molecule, respectively. One noticeable difference between CID and SID is that SID does not require a collision gas for ion activation and is, therefore, directly compatible with the high vacuum requirement of Fourier transform ion cyclotro...
Bimolecular collision rate constants of a model solute are measured in water at T = 259-303 K, a range encompassing both normal and supercooled water. A stable, spherical nitroxide spin probe, perdeuterated 2,2,6,6-tetramethyl-4-oxopiperidine-1-oxyl, is studied using electron paramagnetic resonance spectroscopy (EPR), taking advantage of the fact that the rotational correlation time, τ(R), the ...
It is now well-known that (2)H solid-state NMR techniques can bring a better understanding of the interaction of deuterium with metal atoms in organometallic mononuclear complexes, clusters or nanoparticles. In that context, we have recently obtained experimental quadrupolar coupling constants and asymmetry parameters characteristic of deuterium atoms involved in various bonding situations in r...
Solid-state NMR spectroscopy and GIPAW DFT calculations reveal the pronounced sensitivity of (79/81)Br and (25)Mg quadrupolar coupling constants to subtle aspects of solid state structure which were not previously detected by pXRD methods.
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