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Topic: Hyperfine levels

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	Spartanburg SC \| GoUpstate.com \| Spartanburg Herald-Journal
		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 moment with the magnetic field of the electron.
		The hyperfine structure transition can be used to make a microwave notch filter with very high stability, repeatability and Q factor, which can thus be used as a basis for very precise atomic clocks.
		Typically, the hyperfine structure transition frequency of a particular isotope of caesium or rubidium atoms is used as a basis for these clocks.
	www.goupstate.com /apps/pbcs.dll/section?category=NEWS&template=wiki&text=Hyperfine_structure (809 words)

	Hyperfine structure
		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.
		, the hyperfine splitting is a much smaller perturbation than the fine structure.
		The AVLIS and MLIS processes use hyperfine splitting caused by differences between the mass of atomic nucleus for uranium-235 and uranium-238 to selectively photoionize only the uranium-235 atoms and then separate the ionized particles from the non-ionized ones.
	www.dejavu.org /cgi-bin/get.cgi?ver=93&url=http://articles.gourt.com/%22http%3A%2F%2Farticles.gourt.com%2F%3Farticle%3Dhyperfine (735 words)

	PALS, Laser, Principles
		The electronic configuration of these two levels is described using a spectroscopic notation corresponding to so-called LS coupling which is applicable to atoms in which the spin-orbit interaction is small.
		level does not modify the character of the spatial distribution of the electronic charge, and thus the transition does not produce an oscillating electric-dipole moment.
		These components arise because the magnetic field of the iodine nucleus (nuclear spin 5/2) splits the upper and lower levels into 2 and 4 so-called hyperfine levels, while the selection rules limit the number of possible transitions between these levels to six.
	www.pals.cas.cz /pals/pae221ma.htm (0 words)

	CalendarHome.com - Second - Calendar Encyclopedia
		The second is 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 rotation of the earth.
		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.
	encyclopedia.calendarhome.com /Second.htm (719 words)

	[No title] (Site not responding. Last check: )
		The hyperfine splittings were analyzed to yield values of -0.382(19)% for the hyperfine anomaly and 10.9 GHz/fm/sup 2/ for the field-shift constant; these agree with published values.
		For this purpose the hyperfine structure splitting of the atomic 4s4p /sup 3/P/sub 1/ state was measured.
		In addition, the hyperfine constants of the 3p/sup 2/P/sub 3/2/ level were determined} } @article{JohJulLet96, author={Jones, K. and Julienne, P. and Lett, P. and Phillips, W. and Tiesinga, E. and Williams, C. title={Measurement of the atomic {Na(3P)} lifetime and of retardation in the interaction between two atoms bound in a molecule}, journal={Europhys.
	physics.unr.edu /~tap/BibTeX/all.bib (8502 words)

	[No title]
		As a result, velocity selective excited state hyperfine level populations are obtained, i.e.
		hyperfine absorption line profiles are observed as a direct consequence of the velocity selective optical pumping induced by the frequency comb excitation.
		In the systems where Doppler broadening is negligible, by varying the comb optical frequency spectrum it is possible to directly manipulate the fractional populations of hyperfine ground state levels.
	www.brijuni-conference.irb.hr /ban06.htm (0 words)

	Quantum optics with gamma radiation
		This is a clear signature for the presence of interference effects in nuclear gamma ray absorption towards level mixed nuclear hyperfine levels.
		The minimum energy difference between the levels occurs at the crossing field and is dependent on the strength of the symmetry breaking term, which is determined by the misalignment angle between the applied interactions.
		For example in nuclear physics the principle of level mixing resonances (LMR) is used for the determination of spins, magnetic and quadrupole moments of exotic nuclei that are produced at a few accelerators in the world.
	www.europhysicsnews.com /full/23/article5/article5.html (3997 words)

	The Caesium Fountain Primary Frequency Standard, by National Physical Laboratory at American Buddha Online Library
		The new definition, which remains in force today, states that the second is equal to the duration of exactly 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.
		At room temperature, caesium atoms are equally divided between two internal atomic states - the hyperfine levels of the ground state of the atom referred to in the definition of the second - which differ slightly in energy.
		At the phenomenal level of accuracy now being attained by primary frequency standards, there is a wide range of effects which can cause the microwave transition frequency in the atoms to change from the unperturbed value required by the definition of the second.
	www.american-buddha.com /physiccaesiumfountainprimaryfreq.htm (0 words)

	Hydrogen energies and spectrum
		The basic hydrogen energy level structure is in agreement with the Bohr model.
		The energy levels agree with the earlier Bohr model, and agree with experiment within a small fraction of an electron volt.
		The 2p level is split into a pair of lines by the spin-orbit effect.
	230nsc1.phy-astr.gsu.edu /hbase/hyde.html (396 words)

	second - Information from Reference.com
		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.
		A uniform second was produced by correcting the output of each atomic clock to mean sea level (the rotating geoid), lengthening the second by about 1.
	www.reference.com /search?q=second (1311 words)

	Theory
		Typically, each atomic level is actually made up of many different states that have the same energy.
		Hyperfine splitting occurs because of the interaction between an electron and the nucleus.
		Unfortunately the hyperfine splitting is very small; according to theory it should be smaller by the ratio of the mass of an electron to the mass of a nucleon, or about 1 part in 2000.
	mxp.physics.umn.edu /s03/Projects/S03RbSat/theory.htm (0 words)

	Laser Cooling and Trapping Home Page
		In this level, the atoms can be stored or “shelved” for a long time, since they do not interact neither with the probe laser, nor with the trapping laser (dark trap, large detuning).
		The fraction of atoms transferred to this hyperfine ground level is the signal of the measurement.
		This reduction is achieved by the addition of a weak light field, spatially mode-matched with the trapping field and whose frequency is tuned in-between the two hyperfine levels.
	www.weizmann.ac.il /home/davidson/frame_spectroscopy.html (0 words)

	NRC's Cesium Fountain Clock - FCs1 \| NRC-INMS
		"The second is equal to the duration of 9192631770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom." This definition for the second was adopted in 1967.
		During the lift in the laser beams, the atoms are further cooled to approximately 2μK. Preparation: The atoms are pumped into the upper level of the clock transition.
		The definition of the second (adopted in 1967) is based on the transition between the two hyperfine levels of the ground state of the cesium 133 atom.
	inms-ienm.nrc-cnrc.gc.ca /research/cesium_clock_e.html (0 words)

	Physikalisch-Technische Bundesanstalt (PTB)
		On account of deficiencies of the theory of the moon's motion, and considering the superiority of atomic time standards - the small uncertainty and the unproblematic availability of the second defined as an atomic unit - the concept of the ephemeris second was finally abandoned.
		The second is 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
		In the years that followed, in particular the ammonia beam maser and the hydrogen maser were investigated for their suitability as a frequency standard, but finally it was the transition in the Cs atom proposed by Essen which proved to be particularly suitable for the redefinition of the second.
	www.ptb.de /en/org/4/44/441/info1_e.htm (912 words)

	Kernco, Inc. - CPT Technology
		The sidebands produced, with frequency difference equal to the hyperfine frequency of the ground state, couple the two hyperfine levels of the ground state to the excited P state.
		This causes the following effects: at equilibrium the atoms no longer absorb energy from the two laser radiation fields; the atoms are trapped in the ground state with both hyperfine levels equally populated; a strong hyperfine coherence is created between the two hyperfine ground levels.
		In that case a peak is observed at the hyperfine resonance frequency.
	www.kernco.com /index.php?page=cpt (0 words)

	nature physics portal - looking back - The hydrogen 21-cm line
		Oort had already realized the significance of the discovery — that detection of this spectral line, produced by transitions between hyperfine levels of the ground-state hydrogen atom, would permit measurements of velocities by the Doppler effect.
		The ground-state of the hydrogen atom is a hyperfine doublet the splitting of which, determined by the method of atomic beams, is 1,420.405 Mc./sec.
		We have made rough theoretical estimates of the efficacy of various processes through which energy is exchanged between the hydrogen hyperfine levels and the other thermal reservoirs in the interstellar matter plus radiation complex.
	www.nature.com /physics/looking-back/ewen/index.html (0 words)

	Base unit definitions: Second
		In order to define the unit of time more precisely, the 11th CGPM (1960) adopted a definition given by the International Astronomical Union which was based on the tropical year.
		Experimental work had, however, already shown that an atomic standard of time-interval, based on a transition between two energy levels of an atom or a molecule, could be realized and reproduced much more precisely.
		The second is 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 cesium 133 atom.
	physics.nist.gov /cuu/Units/second.html (163 words)

	Data @ NASA GISS: Molecular Collision Rates Relevant to Microwave and IR Astronomy (Site not responding. Last check: )
		Excitation rates were obtained among the lowest 34 rotational levels for temperatures between 50 and 500 K. plain text file of the published table of rates is available.
		Rate constants are available among the lowest 21 rotational levels and for temperatures between 20 and 300 K as a plain text file.
		A plain text file with the resulting rate constants among the lowest 50 fine-structure levels and for temperatures of 50-350 K is also available.
	data.giss.nasa.gov /mcrates (0 words)

	Rb: Optical Pumping in Rubidium
		The object of this experiment is to measure the Zeeman splitting of the hyperfine structure components of the ground state of rubidium in a known weak magnetic field.
		levels, and hence tend to destroy the spin alignment.
		levels is approximately but not exactly equal so that in principle one should observe four resonant frequencies for each of the isotopes.
	www.physics.utoronto.ca /~phy326/rb/rb.htm (3641 words)

	BIPM - second
		periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.
		It follows that the hyperfine splitting in the ground state of the caesium 133 atom is exactly
		(hfs Cs), is used to denote the frequency of the hyperfine transition in the ground state of the caesium atom.
	www1.bipm.org /en/si/base_units/second.html (292 words)

	Untitled Document
		As described in several prior NASA Tech Briefs articles, an OEO is a hybrid of photonic and electronic components that generates highly spectrally pure microwave radiation, and optical radiation modulated by the microwave radiation, through direct conversion between laser light and microwave radiation in an optoelectronic feedback loop.
		As used here, “atomic cell” signifies a cell containing a vapor, the constituent atoms of which can be made to undergo transitions between quantum states, denoted hyperfine levels, when excited by light in a suitable wavelength range.
		Part of the light leaving the atomic cell could also be used to stabilize the laser at a frequency in the vicinity of the desired hyperfine or other quantum transition.
	www.nasatech.com /Briefs/Dec05/NPO_40958.html (695 words)

	Rubidium D_2 Line
		The splitting between the hyperfine levels is shown with the blue arrows.
		We cannot resolve the hyperfine structure of the excited state as the Doppler broadening of the individual transitions, at room temperature is larger than the difference in energy between them.
		The number of Zeeman sub-levels is equal to the 2F+1, where F is the hyperfine quantum number of that level.
	massey.dur.ac.uk /research/magnetometry/RbD2line/RbD2line.html (0 words)

	Kurucz/News
		Hyperfine and isotopic splitting are included when the data exist but not automatically.
		Since the known energy levels are used when available, the line wavelengths are correct for lines between known energy levels.
		These levels improve the accuracy of the least squares fit, improve the eigenvectors and therefore the gf values, improve the wavelengths, and automatically identify thousands of lines throughout the spectrum.
	kurucz.harvard.edu /news.html (0 words)

	Immortal Fumble Sorcerer (Androcles): Stupid question for Dork Van de merde
		Given: The second is 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 cesium 133 atom.
		A year is 9,192,631,770 * 60 * 60 * 24 * 365.2425 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom.
		What happened to the missing 1,160,365,758,078,260,000 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom's prodigal twin sister?
	users.pandora.be /vdmoortel/dirk/Physics/Fumbles/StupidQuestion.html (193 words)

	Atomic Structure
		Emission spectra and orbital energy levels for hydrogen are calculated and tabularised for the stage of development to this point.
		These are due to (i) the distributed nature of the charge on the electron, and (ii) the dynamic distance of the nucleous from the central point of orbital rotation.
		A detailed comparison of development so far with the modern quantum mechanics/quantum electrodynamics theory is also presented, together with detailed discussions on (i) emission spectra, (ii) orbital energy levels and intervals, (iii) the Lamb Shift, (iv) the mechanics of orbital transitions, and (v) ionisation orbitals.
	www.relativitydomains.com /Physics (639 words)

	Physics Today September 2001
		Chronologically, the first critical experiment was the discovery by John Nafe, Edward Nelson, and I. Rabi that the hyperfine separation of atomic hydrogen was different from that predicted by the Dirac theory of the electron.
		atomic hyperfine structure levels in atomic hydrogen was wrong by many times the experimental error of their new measurements.
		Surely the Nafe, Nelson, and Rabi hyperfine structure experiment was not invented to verify the renormalized electrodynamics, since it was invented by Rabi and me in late 1944.
	physicstoday.org /pt/vol-54/iss-9/p78b.html (0 words)

	ROOT MODULES
		The nuclear spin I of the former isotope is 3/2 and of the latter isotope is 5/2.
		This implies a redistribution of population among the multiple levels (hyperfine levels or even Zeeman levels of a hyperfine level) due to a series of absorption emission cycles.
		The frequency stabilized hyperfine laser beam from the laser diode (20), is reflected by the pair of mirrors (23a) and (23b) onto the mirror (4) which reflects it to the trapping cell.
	www.iisc.ernet.in /currsci/jan25/articles24.htm (4860 words)

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