Search results
Results from the WOW.Com Content Network
Contributing structures of the carbonate ion. In chemistry, resonance, also called mesomerism, is a way of describing bonding in certain molecules or polyatomic ions by the combination of several contributing structures (or forms, [1] also variously known as resonance structures or canonical structures) into a resonance hybrid (or hybrid structure) in valence bond theory.
Resonance hyper-Raman spectroscopy: Excitation of the sample occurs by two-photon absorption, rather than by absorption of a single photon. This arrangement allows for excitation of modes that are forbidden in ordinary resonance Raman spectroscopy, with intensity enhancement due to resonance, and also simplifies collection of scattered light.
Broadband acoustic resonance dissolution spectroscopy (BARDS) is a technique in analytical chemistry. Developed in the late 2000s, [ 1 ] it involves the analysis of the changes in sound frequency generated when a solute dissolves in a solvent , by harnessing the hot chocolate effect .
Triple resonance experiments are a set of multi-dimensional nuclear magnetic resonance spectroscopy (NMR) experiments that link three types of atomic nuclei, most typically consisting of 1 H, 15 N and 13 C. These experiments are often used to assign specific resonance signals to specific atoms in an isotopically-enriched protein.
The analysis of such multiplets (which can be much more complicated than the ones shown here) provides important clues to the structure of the molecule being studied. The simple rules for the spin-spin splitting of NMR signals described above apply only if the chemical shifts of the coupling partners are substantially larger than the coupling ...
As a consequence, the reflectivity value at the resonance angle is dumped. [46] The propagation constant of the polaritons can be modified by varying the dielectric material. This modification causes resonance angle shifting as in the example shown in Figure 10, from θ 1 to θ 2 due to the change on the surface plasmon propagation constant.
with a sharp resonance in the reaction cross section at 6.385 MeV of only 1.8 keV. [3] Since the incident 15 N ion loses energy along its trajectory in the material it must have an energy higher than the resonance energy to induce the nuclear reaction with hydrogen nuclei deeper in the target.
A model resonance ionization mass spectrometry (RIMS) set-up consists of a laser system (consisting of multiple lasers), sample from which the atoms are derived, and a suitable mass spectrometer which mass-selectively detects the photo ions created from resonance. In resonant ionization, atoms or molecules from ground state are excited to ...