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NMR Nuclear magnetic resonance Nuclear magnetic resonance (NMR) is a physical phenomenon in which nuclei in a magnetic field absorb and reemit electromagnetic radiation. This energy is at a specific resonance frequency which depends on the strength of the magnetic field and the magnetic properties of the isotope of the atoms; in practical applications, the frequency is similar to VHF VHF and UHF UHF television broadcasts (60–1000 MHz). NMR allows the observation of specific quantum mechanical magnetic properties of the atomic nucleus. Many scientific techniques exploit NMR phenomena to study molecular physics, crystals, and noncrystalline materials through nuclear magnetic resonance spectroscopy [...More...]  "NMR" on: Wikipedia Yahoo 

Stern–Gerlach Experiment The Stern–Gerlach experiment Stern–Gerlach experiment demonstrated that the spatial orientation of angular momentum is quantized. It demonstrated that atomicscale systems have intrinsically quantum properties. In the original experiment, silver atoms were sent through a spatially varying magnetic field, which deflected them before they struck a detector screen, such as a glass slide. If the particles have a magnetic moment, the magnetic field gradient deflects them from a straight path. The screen reveals discrete points of accumulation rather than a continuous distribution[1], owing to the quantum nature of spin [...More...]  "Stern–Gerlach Experiment" on: Wikipedia Yahoo 

Spectral Resolution The spectral resolution of a spectrograph, or, more generally, of a frequency spectrum, is a measure of its ability to resolve features in the electromagnetic spectrum. It is usually denoted by Δ λ displaystyle Delta lambda , and is closely related to the resolving power of the spectrograph, defined as R = λ Δ λ displaystyle R= lambda over Delta lambda , where Δ λ displaystyle Delta lambda is the smallest difference in wavelengths that can be distinguished at a wavelength of λ displaystyle lambda . For example, the Space Telescope Imaging Spectrograph Spectrograph (STIS) can distinguish features 0.17 nm apart at a wavelength of 1000 nm, giving it a resolution of 0.17 nm and a resolving power of about 5,900 [...More...]  "Spectral Resolution" on: Wikipedia Yahoo 

Boron11 Boron Boron (5B) naturally occurs as isotopes 10and 11B, the latter of which makes up about 80% of natural boron. There are 14 radioisotopes that have been discovered, with mass numbers from 6 to 21, all with short halflives, the longest being that of 8B, with a halflife of only 770 milliseconds (ms) and 12B with a halflife of 20.2 ms [...More...]  "Boron11" on: Wikipedia Yahoo 

Phosphorus31 Although phosphorus (15P) has 23 isotopes from 24P to 46P, only one of these isotopes is stable 31P; as such, it is considered a monoisotopic element. The longestlived radioactive isotopes are 33P with a halflife of 25.34 days and 32P with a halflife of 14.263 days. All others have lived under 2.5 minutes, most under a second. The least stable is 25P with a halflife shorter than 30 nanoseconds—the halflife of 24P is unknown.Contents1 Radioactive isotopes1.1 Phosphorus32 1.2 Phosphorus332 List of isotopes2.1 Notes3 References 4 External linksRadioactive isotopes[edit] Phosphorus32[edit] 32P, a betaemitter (1.71 MeV) with a halflife of 14.3 days, is used routinely in lifescience laboratories, primarily to produce radiolabeled DNA DNA and RNA RNA probe, e.g. for use in Northern blots or Southern blots [...More...]  "Phosphorus31" on: Wikipedia Yahoo 

Chlorine35 Chlorine Chlorine (17Cl) has 24 isotopes with mass numbers ranging from 28Cl to 51Cl and 2 isomers (34mCl and 38mCl). There are two principal stable isotopes, 35Cl (75.78%) and 37Cl (24.22%), giving chlorine a standard atomic weight of 35.45. The longestlived radioactive isotope is 36Cl, which has a halflife of 301,000 years. All other isotopes have halflives under 1 hour, many less than one second. The shortestlived are 29Cl and 30Cl, with halflives less than 20 and 30 nanoseconds, respectively—the halflife of 28Cl is unknown.Contents1 Chlorine36 (36Cl) 2 List of isotopes2.1 Notes3 References 4 External links Chlorine36 (36Cl)[edit] Main article: Chlorine36 Trace amounts of radioactive 36Cl exist in the environment, in a ratio of about 7×10−13 to 1 with stable isotopes. 36Cl is produced in the atmosphere by spallation of 36Ar by interactions with cosmic ray protons [...More...]  "Chlorine35" on: Wikipedia Yahoo 

Cadmium113 Naturally occurring cadmium (48Cd) is composed of 8 isotopes. For two of them, natural radioactivity was observed, and three others are predicted to be radioactive but their decays were never observed, due to extremely long halflife times. The two natural radioactive isotopes are 113Cd (beta decay, halflife is 8.04 × 1015 years) and 116Cd (twoneutrino double beta decay, halflife is 2.8 × 1019 years). The other three are 106Cd, 108Cd (double electron capture), and 114Cd (double beta decay); only lower limits on their halflife times have been set. At least three isotopes—110Cd, 111Cd, and 112Cd—are absolutely stable (except, theoretically, to spontaneous fission). Among the isotopes absent in the natural cadmium, the most longlived are 109Cd with a halflife of 462.6 days, and 115Cd with a halflife of 53.46 hours. All of the remaining radioactive isotopes have halflives that are less than 2.5 hours and the majority of these have halflives that are less than 5 minutes [...More...]  "Cadmium113" on: Wikipedia Yahoo 

Carbon13 Carbon13 (13C) is a natural, stable isotope of carbon with a nucleus containing six protons and seven neutrons. As one of the environmental isotopes, it makes up about 1.1% of all natural carbon on Earth. Contents1 Detection by mass spectrometry 2 Uses in science 3 See also 4 NotesDetection by mass spectrometry[edit] A mass spectrum of an organic compound will usually contain a small peak of one mass unit greater than the apparent molecular ion peak (M) of the whole molecule. This is known as the M+1 peak and comes from the handful of molecules that contain a 13C atom in place of a 12C. A molecule containing one carbon atom will be expected to have an M+1 peak of approximately 1.1% of the size of the M peak, as 1.1% of the molecules will have a 13C rather than a 12C [...More...]  "Carbon13" on: Wikipedia Yahoo 

Xenon129 Naturally occurring xenon (54Xe) is made of eight stable isotopes and one very longlived isotope. (124Xe, 126Xe, and 134Xe are predicted to undergo double beta decay,[citation needed] but this has never been observed in these isotopes, so they are considered to be stable.)[3][4][not in citation given] Xenon Xenon has the secondhighest number of stable isotopes. Only tin, with 10 stable isotopes, has more.[5] Beyond these stable forms, over 30 unstable isotopes and isomers have been studied, the longestlived of which is 136Xe, which undergoes double beta decay with a halflife of 2.165 ± 0.016(stat) ± 0.059(sys) ×1021 years[1] with the next longest lived being 127Xe with a halflife of 36.345 days. Of known isomers, the longestlived is 131mXe with a halflife of 11.934 days [...More...]  "Xenon129" on: Wikipedia Yahoo 

Nuclide A nuclide (from nucleus, also known as nuclear species) is an atomic species characterized by the specific constitution of its nucleus, i.e., by its number of protons Z, its number of neutrons N, and its nuclear energy state.[1] The word nuclide was proposed[2] by Truman P. Kohman[3] in 1947. Kohman originally suggested nuclide as referring to a "species of atom characterized by the constitution of its nucleus" defined by containing a certain number of neutrons and protons [...More...]  "Nuclide" on: Wikipedia Yahoo 

Platinum195 Natural platinum (78Pt) occurs in six stable isotopes (192Pt, 194Pt, 195Pt, 196Pt, 198Pt) and one very longlived (halflife 6.50×1011 years) radioisotope (190Pt). There are also 31 known artificial radioisotopes, the longestlived of which is 193Pt with a halflife of 50 years [...More...]  "Platinum195" on: Wikipedia Yahoo 

Angular Momentum In physics, angular momentum (rarely, moment of momentum or rotational momentum) is the rotational equivalent of linear momentum. It is an important quantity in physics because it is a conserved quantity – the total angular momentum of a system remains constant unless acted on by an external torque. In three dimensions, the angular momentum for a point particle is a pseudovector r×p, the cross product of the particle's position vector r (relative to some origin) and its momentum vector p = mv. This definition can be applied to each point in continua like solids or fluids, or physical fields. Unlike momentum, angular momentum does depend on where the origin is chosen, since the particle's position is measured from it [...More...]  "Angular Momentum" on: Wikipedia Yahoo 

Neutrons 5000000000000000000♠0 e 3021799999999999999♠(−2±8)×10−22 e (experimental limits)[4]Electric dipole moment < 6974290000000000000♠2.9×10−26 e⋅cm (experimental upper limit)Electric polarizability 6997116000000000000♠1.16(15)×10−3 fm3Magnetic moment 3026033763500000000♠−0.96623650(23)×10−26 J·T−1[3] 3002895812437000000♠−1.04187563(25)×10−3 μB[3] 2999808695726999999♠−1.91304273(45) μN[3]Magnetic polarizability 6996370000000000000♠3.7(20)×10−4 fm3Spin 1/2Isospin −1/2Parity +1Condensed I(JP) = 1/2(1/2+)The neutron is a subatomic particle, symbol n or n0, with no net electric charge and a mass slightly larger than that of a proton. Protons and neutrons constitute the nuclei of atoms [...More...]  "Neutrons" on: Wikipedia Yahoo 

Gradient In mathematics, the gradient is a multivariable generalization of the derivative. While a derivative can be defined on functions of a single variable, for functions of several variables, the gradient takes its place. The gradient is a vectorvalued function, as opposed to a derivative, which is scalarvalued. Like the derivative, the gradient represents the slope of the tangent of the graph of the function. More precisely, the gradient points in the direction of the greatest rate of increase of the function, and its magnitude is the slope of the graph in that direction. The components of the gradient in coordinates are the coefficients of the variables in the equation of the tangent space to the graph [...More...]  "Gradient" on: Wikipedia Yahoo 

Perpendicular In elementary geometry, the property of being perpendicular (perpendicularity) is the relationship between two lines which meet at a right angle (90 degrees). The property extends to other related geometric objects. A line is said to be perpendicular to another line if the two lines intersect at a right angle.[2] Explicitly, a first line is perpendicular to a second line if (1) the two lines meet; and (2) at the point of intersection the straight angle on one side of the first line is cut by the second line into two congruent angles. Perpendicularity can be shown to be symmetric, meaning if a first line is perpendicular to a second line, then the second line is also perpendicular to the first. For this reason, we may speak of two lines as being perpendicular (to each other) without specifying an order. Perpendicularity easily extends to segments and rays [...More...]  "Perpendicular" on: Wikipedia Yahoo 

Zeeman Effect The Zeeman effect Zeeman effect (/ˈzeɪmən/; Dutch pronunciation: [ˈzeːmɑn]), named after the Dutch physicist Pieter Zeeman, is the effect of splitting a spectral line into several components in the presence of a static magnetic field. It is analogous to the Stark effect, the splitting of a spectral line into several components in the presence of an electric field. Also similar to the Stark effect, transitions between different components have, in general, different intensities, with some being entirely forbidden (in the dipole approximation), as governed by the selection rules. Since the distance between the Zeeman sublevels is a function of magnetic field strength, this effect can be used to measure magnetic field strength, e.g. that of the Sun Sun and other stars or in laboratory plasmas [...More...]  "Zeeman Effect" on: Wikipedia Yahoo 