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	Hyperfine structure - Wikipedia, the free encyclopedia
		In atomic physics, hyperfine structure is a small perturbation in the energy levels (or spectra) of atoms or molecules due to the magnetic dipole-dipole interaction, arising from the interaction of the nuclear magnetic dipole with the magnetic field of the electron.
		Carl Sagan and Frank Drake considered the hyperfine transition of hydrogen to be a sufficiently universal phenomenon so as to be used as a base unit of time and length on the Pioneer plaque and later Voyager Golden Record.
		Typically, the hyperfine structure transition frequency of a particular isotope of caesium or rubidium atoms is used as a basis for these clocks.
	en.wikipedia.org /wiki/Hyperfine_structure (734 words)

	[ michigan-land-for-sale.com \| Hyperfine transition Resources ] (Site not responding. Last check: 2007-10-31)
		In atomic physics, hyperfine structure is a petty perturbation in the muscle identicals (or spectra) of atoms or molecules due to the magnetic dipole-dipole interaction, arising from the interaction of the nuclear bewitching dipole with the bewitching tillage of the electron.
		The hyperfine architecture progress can be used to fiddle with a microwave notch trickle with very gargantuan stability, repeatability 'n Q factor, which can thus be used as a ground for very very atomic clocks.
		Typically, the hyperfine architecture progress iteration of a painstaking isotope of caesium or rubidium atoms is used as a ground for these clocks.
	www.michigan-land-for-sale.com /Hyperfine_transition (799 words)

	Second - Wikipedia, the free encyclopedia
		Under the International System of Units, the second is currently defined as the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom.
		With the development of the atomic clock, it was decided to use atomic clocks as the basis of the definition of the second, rather than the revolution of the Earth around the Sun.
		Using a common-view measurement method based on the received signals from radio station WWV, they determined the orbital motion of the Moon about the Earth, from which the apparent motion of the Sun could be inferred, in terms of time as measured by an atomic clock.
	en.wikipedia.org /wiki/Second (897 words)

	I.D. Vagner, Yu.A. Bychkov, A.M. Dyugaev, T. Maniv, A. Rozhavskii, P. Wyder: Hyperfine Interactions in Quantum Hall and ... (Site not responding. Last check: 2007-10-31)
		In two-dimensional electron systems under strong magnetic fields the contact hyperfine interaction, resulting in the simultaneous spin flip of the nuclear and the electron spins (flip-flop), is severely restricted by energy conservation, since the electron spin splitting is orders of magnitudes larger than the nuclear one.
		The hyperfine field, caused by the nonequilibrium nuclear spin population [61], breaks the spin symmetry of charged carriers.
		Under the topologically nontrivial spatial nuclear spin distribution the hyperfine field produces an adiabatically slow time variation of the Berry phase of the electron wave function, analogous to one which emerges in standard ABE in textured mesoscopic rings [64,65] and in Aharonov-Casher effect [66].
	www.magniel.com /hmtj/papers/vbdmprw00/vbdmprw.html (8325 words)

	Hyperfine structure (Site not responding. Last check: 2007-10-31)
		Hyperfine structure is a small perturbation in the energy levels (or spectral) of atoms due to the proton-electron dipole moment interaction.
		The amount of correction to the Bohr energy levels due to "hyperfine splitting" is on the order of:
		Also hyperfine structure gives the 21 cm line observed in HI region in interstellar medium.
	www.xasa.com /wiki/en/wikipedia/h/hy/hyperfine_structure.html (218 words)

	Hyperfine structure (Site not responding. Last check: 2007-10-31)
		Thinking classically, the electron moving around the nucleus has a magnetic dipole moment, as it is charged.
		However, there is also hyperfine splitting for s-shell electrons which do not have an angular momentum, and then it is even stronger, as the electron probability distribution does not vanish in the nucleus.
		The amount of correction to the Bohr energy levels due to hyperfine splitting of the hydrogen atom is on the order of: :
	hyperfine-structure.borgfind.com (508 words)

	Antiprotons probe hyperfine splitting (November 2002) - News - PhysicsWeb
		Hyperfine splitting is a familiar phenomenon in atomic physics in which magnetic interactions between the nucleus and the electrons split the electronic energy levels into sublevels.
		This is caused by the magnetic interaction between the orbital angular momentum of the anti-proton and the spin of the electron.
		Then by firing a laser pulse into the helium the researchers were able to reduce the population of the lower level relative to the higher level by sending antiprotons in atoms lying in the lower level into atomic states from which they instantly annihilated.
	www.physicsweb.org /articles/news/6/11/18/1 (393 words)

	Theory Group : Hyperfine interaction
		It was outlined in [1] that in two-dimensional electron systems under strong magnetic fields the contact hyperfine interaction, resulting in the simultaneous spin flip of the nuclear and the electron spins (flip-flop) (Fig.1) is severely restricted by energy conservation, since the electron spin splitting is orders of magnitudes larger than the nuclear one.
		The role of the contact hyperfine interaction is to replace the external magnetic field which splits the conduction band and creates the magnetisation of the carriers.
		We have suggested [17], that the hyperfine interaction between the conduction electron spins and nuclear spins may result in universal residual resistivity in clean metals at low temperatures.
	www.magniel.com /group/r_hyper.html (1540 words)

	Description of Research--Gary S. Collins
		Detrapping of hydrogen from vacancy complexes was observed during annealing at temperatures above room temperature and was analyzed to estimate of the binding energy of hydrogen in four different vacancy complexes using a model of diffusion in a medium with traps [43].
		Relaxation that was observed in the signal of a hydrogen-decorated 3V complex in platinum [34] was attributed to 'cage' motion of the hydrogen atom or probe in the complex, with a measured activation energy of 0.34(5) eV [52].
		Pressure dependence of the hyperfine field at a probe in a trivacancy complex in Ni was measured and compared with the pressure dependence measured at a defect-free substitutional site [40].
	defects.physics.wsu.edu /description.htm (6384 words)

	Hyperfine Structure
		The quantum number f has possible values f=j+1/2,j-1/2 since the proton is spin 1/2, and hence every energy level associated with a particular set of quantum numbers n, l, and j will be split into two levels of slightly different energy, depending on the relative orientation of the proton magnetic dipole with the electron state.
		Consider first the case l=0, since the hyperfine splitting of the hydrogen atom ground state is of the most interest.
		Figure 7 shows a revised version of the structure of the hydrogen atom, including the Lamb shift and hyperfine structure.
	www.pha.jhu.edu /~rt19/hydro/node9.html (798 words)

	Gemini Observatory (Site not responding. Last check: 2007-10-31)
		A good example would be the hyperfine structure (HFS) lines due to interaction in the internal magnetic field produced by the motion of the electrons of an atom and the spin magnetic moment of its nucleus.
		While hyperfine transitions are common in the radio range (the best known is the 21-centimeter line of neutral hydrogen), at shorter wavelengths atomic hyperfine structure has seldom been resolved in emission spectra because the velocity separation between hyperfine components is proportional to wavelength.
		More details can be found in the paper "Hyperfine splitting of [Al VI] 3.66-micron and the Al isotopic ratio in NGC 6302", by S. Casassus, P. J Storey, M. Barlow and P. Roche to appear in the Monthly Notices of the Royal Astronomical Society.
	www.gemini.edu /index.php?option=content&task=view&id=127.html (705 words)

	Hyperfine anomaly
		The atomic electron-nuclear hyperfine structure (hfs) interactions have been used to obtain nuclear spins and electric and magnetic moments.
		Since the discovery of the hyperfine anomaly there were quite a lot of work done both theoretically and experimentally.
		With the advent of combined laser/rf spectroscopy a number of measurements were done where the hyperfine structure were measured with high accuracy.
	www.mna.hkr.se /~pej/hfatext.htm (1261 words)

	Hyperfine
		I guess I have a while yet to look at the hyperfine structure of things, to appreciate the spider webs and moss, the mushrooms and weathered driftwood along some deserted beaches.
		Continuing with my search for the hyperfine structure of the world I walked out across the campus headed for that wall down by the alumni office.
		On Foss Hill I stopped at the observatory to look at the moss on the north wall; the growth there was not extensive and rather subtle but still worth a look and a few photos.
	www.wesleyan.edu /av/Hyperfine.html (1787 words)

	M\"ossbauer studies of hyperfine fields in disordered Fe$_{\bf 2}$CrAl (Site not responding. Last check: 2007-10-31)
		The M\"ossbauer spectra were recorded over a range of temperature from 40 to 296 K. The M\"ossbauer spectra showed the co-existence of a paramagnetic part with a magnetic hyperfine portion at all recorded temperatures.
		Even with the distribution in the magnetic hyperfine field, the average hyperfine field follows the $(T/T_{\rm c})^{3/2}$ law.
		The paramagnetic part of the hyperfine field is explained in terms of the clustering of Cr atoms.
	www.ias.ac.in /pramana/v59/p531/abs.htm (113 words)

	A Search for the Tritium Hyperfine Line from Nearby Stars
		The tritium frequency is highly attractive for SETI work because the isotope is cosmically rare and the tritium hyperfine line is centered in the SETI waterhole region of the terrestrial microwave window.
		The neutral tritium ground-state hyperfine transition line at 1516.701470 9064(16) MHz (Mathur et al., 1967) is centered in the SETI waterhole region of the terrestrial microwave window (Billingham and Oliver, 1973) which lies between the H and OH spectral lines.
		A search centered on the tritium hyperfine line for 108 assorted astronomical objects, with emphasis on 53 nearby stars, was conducted from 28 June to 10 July 1983 using the 26-m radiotelescope at the University of California's Hat Creek Radio Observatory, located about 270 miles north of the Berkeley, California, campus.
	www.rfreitas.com /Astro/TritiumSearch1986.htm (1677 words)

	WS0506 (Site not responding. Last check: 2007-10-31)
		The study of the hyperfine anomaly of neutron rich nuclei, in particular, neutron halo nuclei, can give a very specific and unique way to measure their neutron distribution and confirm a halo structure.
		The hyperfine structure anomaly in Be ions was calculated with a realistic electronic wave function, obtained as a solution of the Dirac equation.
		As the result it was found, that the hyperfine anomaly is very sensitive to the weights of partial states in the ground state nuclear wave function.
	www.gsi.de /forschung/ap/seminar-WS0506.php?id=seminar61 (195 words)

	Spin Stripes of the 2D Electron Gas in a Periodic Hyperfine Field (Site not responding. Last check: 2007-10-31)
		A novel periodic spin structure induced in a two-dimensional electron gas by a periodic hyperfine field is proposed and theoretically studied.
		The periodic nuclear magnetization is created, via the hyperfine electron-nuclear spin interaction, by the light induced periodic electron spin grating.
		The optically excited electron spin polarization rapidly vanishes after the laser beam grating is switched off, while the inhomogeneous nuclear spin polarization remains for a sufficiently long time, which makes possible the writing and storage of information.
	pubs.acs.org /cgi-bin/abstract.cgi/nalefd/2004/4/i05/abs/nl035008w.html (208 words)

	Hyperfine spectroscopy on the $\mth{6P_{3/2}}$ state of $\chem{^{133}Cs}$ using coherent control (Site not responding. Last check: 2007-10-31)
		Hyperfine spectroscopy on the $\mth{6P_{3/2}}$ state of $\chem{^{133}Cs}$ using coherent control
		The spectrum of a weak probe beam shows Doppler-free transparency peaks when the strong control beam is resonant with a neighboring hyperfine transition.
		Using an acousto-optic modulator to calibrate the frequency of the control beam, we measure hyperfine intervals in the 6P
	www.edpsciences.org /articles/epl/abs/2005/23/epl9053/epl9053.html (163 words)

	35 th Anniversary of Hyperfine Interactions at La Plata (Site not responding. Last check: 2007-10-31)
		The International Workshop "35th Anniversary of Hyperfine Interactions at La Plata" will be held in La Plata, Argentina, from 7th to 10th November, 2005 and is organized to celebrate 35 years of constant work in the field of Hyperfine Interactions at the National University of La Plata (UNLP).
		Relevant scientists in hyperfine interactions have been invited to the conference.
		The research groups of Bonn and Göttingen have had a close contact with the group at La Plata from the very beginning, and specialists in hyperfine interactions from Brazil, with whom a tight cooperation is kept, are also likely to participate in the event.
	www.fisica.unlp.edu.ar /annivlp/english/aniversa.htm (447 words)

	Atomic and molecular physics : Hyperfine structure
		Frequency measurements and hyperfine structure of the R(85)330 transition of molecular iodine with a femtosecond optical comb
		Hyperfine interactions and perturbation effects in the B0u+(3Pi) state of 127I2
		Measurements of the indium hyperfine structure in an atmospheric-pressure flame by use of diode-laser-induced fluorescence
	www.opticsinfobase.org /ocisdirectory/020_2930.cfm (395 words)

	Springer WienNewYork - Applied Magnetic Resonance
		C hyperfine studies, together with data for protons in specific ring substituents, confirm the high asymmetry correlated with only one dominant H-bond in the A1 site of PS I, which is consistent with the structure model derived from X-ray structure (1JB0) for the ground state of the PS I protein complex.
		O hyperfine tensors measured for the A1 site of PS I yield high hyperfine coupling constants but very small asymmetry for the two carbonyl groups.
		O hyperfine coupling itself appears to depend on the electrostatics seen by the radical anion.
	www.springer.at /periodicals/article_issue.jsp?articleID=xxxxxxxxxxx7xxxxxx393109&volumeIssueID=xxxxxxxxx175xxxxxx386108&periodicalID=0937-9347&supplement=false (361 words)

	CBPF/MCT - Eletronic Structure Group
		We are investigating its electronic structure and the interaction with the ligand NO. We are calculating the hyperfine parameters at the N atoms, to help in the interpretation of EPR and ENDOR spectra.
		Our interest in micas, particularly annite, is related to the hyperfine interactions as measured by Mössbauer spectroscopy.
		Currently we are investigating the magnetic order of annite by calculating the Heisenberg exchange constant: mica is a natural laboratory to study 2D magnetism.
	www.cbpf.br /GrupPesq/ElectronStruct.html (1245 words)

	Effect of Hyperfine Structure on Line Shape
		In order to show the importance of the hyperfine structure in determining the line shape, Figure 7.13 shows the shape that the predicted line would have if the hyperfine transitions were ignored.
		The effect of the hyperfine components is to reduce the absorption necessary to obtain the same column density in the model.
		As a further possibility, it is interesting to note that the model which did not include the hyperfine components agrees well for the line of sight clouds.
	www.mpifr-bonn.mpg.de /staff/epolehampton/thesis/node134.html (336 words)

	SCM: ADF User's Guide
		ESR is a block-type keyword that invokes calculation of the g-tensor [95] as well as the Nuclear Magnetic Dipole Hyperfine interaction (A-tensor) [96].
		In case (1), the program will also calculate and print the Nuclear Magnetic Dipole Hyperfine interaction, but the terms due to the spin-polarization density at the nucleus are absent.
		For the computation of the A-tensor, the Nuclear Magnetic Dipole Hyperfine interaction, an accurate evaluation of the spin-polarization density at the nucleus is important.
	www.scm.com /Doc/Doc2005.01/ADF/ADFUsersGuide/page109.html (429 words)

	Electron-Nuclear Double Resonance and Hyperfine Sublevel Correlation Spectroscopic Studies of Flavodoxin Mutants from ...
		Electron-Nuclear Double Resonance and Hyperfine Sublevel Correlation Spectroscopic Studies of Flavodoxin Mutants from Anabaena sp.
		The largest hyperfine couplings observed by ENDOR, in native flavodoxin semiquinone, correspond to the CH (8) group of
		TABLE 1 Hyperfine coupling constants determined by ENDOR spectroscopy for CH (10), and H(6) protons of the flavin ring in the different flavodoxin semiquinone forms from Anabaena PCC 7119
	www.biophysj.org /cgi/content/full/77/3/1712 (4407 words)

	Advanced Physics Forums - multipole exapnsion of hyperfine interaction (Site not responding. Last check: 2007-10-31)
		use the electric dipole operator in the matrix element calculating the transition probability to move between the hyperfine states), you'll see that to first order it's simply zero or very close to that.
		If you take the corrections for 2nd order it might give you some finite probability (this is why it's called a forbidden transition), but small.
		Actually, in some sensitive experiments, such as very accurate atomic clocks, people use exactly these forbidden transitions, as they usually suffer much less from broadening and other noise effects, and hence if you CAN measure them you have a good and sensitive clock.
	www.advancedphysics.org /forum/printthread.php?t=3557 (186 words)

	Springer WienNewYork - Applied Magnetic Resonance
		Hyperfine Structure of ESR Spectra as a Probe for Heisenberg Exchange Couplings in Nitroxide Triradicals Serving as Building Blocks for Molecule-Based Ferrimagnets
		for g = 2), which is on the same order as the hyperfine coupling A of magnetic nuclei such as nitrogen atoms of nitroxide radicals, the magnitude of J can be determined from the hyperfine splitting pattern of ESR spectra in solutions.
		We demonstrate an application of hyperfine ESR spectroscopy as a probe for the exchange coupling to a series of organic oligoradicals, which the authors have recently developed as building blocks for molecule-based magnetic materials.
	www.springer.at /periodicals/article_issue.jsp?articleID=xxxxxxxxxx38xxxxxx300109&volumeIssueID=xxxxxxxxxxx3xxxxxx300108&periodicalID=0937-9347&supplement=false (175 words)

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