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The hyperfine structures of the ground states in the ${}^{3}$He$^{2+} \mu^{-} e^{-}$ and ${}^{4}$He$^{2+} \mu^{-} e^{-}$ helium-muonic atoms are investigated with the use of highly accurate variational wave functions. The differences between corresponding levels of hyperfine structure (i.e. hyperfine splittings) are determined to very high numerical accuracy. In particular, we have found that the hyperfine structure splitting in the ground state of the ${}^{4}$He$^{2+} \mu^{-} e^{-}$ atom is $\Delta \nu \approx 4464.55454(3)$ $MHz$, while analogous splitting for the ${}^{3}$He$^{2+}\mu^{-}e^{-}$ atom is $\Delta \nu \approx 4166.43547(3)$.

We store and control ultra-cold atoms in a new type of trap using magnetic fields of vortices in a high temperature superconducting micro-structure. This is the first time ultra-cold atoms have been trapped in the field of magnetic flux quanta. We generate the attractive trapping potential for the atoms by combining the magnetic field of a superconductor in the remanent state with external homogeneous magnetic fields. We show the control of crucial atom trap characteristics such as an efficient intrinsic loading mechanism, spatial positioning of the trapped atoms and the vortex density in the superconductor. The measured trap characteristics are in good agreement with our numerical simulations.

Includes bibliography

Includes bibliography

Book digitized by Google from the library of Harvard University and uploaded to the Internet Archive by user tpb.

This paper is in the public domain in USA. Metadata comes from the CrossRef API, see full record in the source URL below.

This paper is in the public domain in USA. Metadata comes from the CrossRef API, see full record in the source URL below.

This article is from BMC Research Notes , volume 6 . Abstract Background: Hydrogen atoms represent about half of the total number of atoms in proteins and are often involved in substrate recognition and catalysis. Unfortunately, X-ray protein crystallography at usual resolution fails to access directly their positioning, mainly because light atoms display weak contributions to diffraction. However, sub-Ångstrom diffraction data, careful modeling and a proper refinement strategy can allow the positioning of a significant part of hydrogen atoms. Results: A comprehensive study on the X-ray structure of the diisopropyl-fluorophosphatase (DFPase) was performed, and the hydrogen atoms were modeled, including those of solvent molecules. This model was compared to the available neutron structure of DFPase, and differences in the protein and the active site solvation were noticed. Conclusions: A further examination of the DFPase X-ray structure provides substantial evidence about the presence of an activated water molecule that may constitute an interesting piece of information as regard to the enzymatic hydrolysis mechanism.

This paper is in the public domain in USA. Metadata comes from the CrossRef API, see full record in the source URL below.

"The Abundance of the Elements in Relation to the Hydrogen-Helium Structure of the Atoms" is an article from Proceedings of the National Academy of Sciences of the United States of America, Volume 2 . View more articles from Proceedings of the National Academy of Sciences of the United States of America . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-83937

"The Abundance of the Elements in Relation to the Hydrogen-Helium Structure of the Atoms" is an article from Proceedings of the National Academy of Sciences of the United States of America, Volume 2 . View more articles from Proceedings of the National Academy of Sciences of the United States of America . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-83937

"The Abundance of the Elements in Relation to the Hydrogen-Helium Structure of the Atoms" is an article from Proceedings of the National Academy of Sciences of the United States of America, Volume 2 . View more articles from Proceedings of the National Academy of Sciences of the United States of America . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-83937

"The Abundance of the Elements in Relation to the Hydrogen-Helium Structure of the Atoms" is an article from Proceedings of the National Academy of Sciences of the United States of America, Volume 2 . View more articles from Proceedings of the National Academy of Sciences of the United States of America . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-83937

"The Abundance of the Elements in Relation to the Hydrogen-Helium Structure of the Atoms" is an article from Proceedings of the National Academy of Sciences of the United States of America, Volume 2 . View more articles from Proceedings of the National Academy of Sciences of the United States of America . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-83937

We present systematic results, based on density functional calculations, for the structure and energetics of $^3$He and $^4$He nanodroplets doped with alkaline earth atoms. We predict that alkaline earth atoms from Mg to Ba go to the center of $^3$He drops, whereas Ca, Sr, and Ba reside in a deep dimple at the surface of $^4$He drops, and Mg is at their center. For Ca and Sr, the structure of the dimples is shown to be very sensitive to the He-alkaline earth pair potentials used in the calculations. The $5s5p\leftarrow5s^2$ transition of strontium atoms attached to helium nanodroplets of either isotope has been probed in absorption experiments. The spectra show that strontium is solvated inside $^3$He nanodroplets, supporting the calculations. In the light of our findings, we emphasize the relevance of the heavier alkaline earth atoms for analyzing mixed $^3$He-$^4$He nanodroplets, and in particular, we suggest their use to experimentally probe the $^3$He-$^4$He interface.

THE STRUCTURE OF ATOMS AND MOLECULES  V. Kondratyev

THE STRUCTURE OF ATOMS AND MOLECULES  V. Kondratyev

THE STRUCTURE OF ATOMS AND MOLECULES  V. Kondratyev

Book Source: Digital Library of India Item 2015.167604 dc.contributor.author: Alfred Stock dc.date.accessioned: 2015-07-07T01:02:05Z dc.date.available: 2015-07-07T01:02:05Z dc.date.digitalpublicationdate: 2004-07-24 dc.date.citation: 1923 dc.identifier: RMSC, IIIT-H dc.identifier.barcode: 2999990039648 dc.identifier.origpath: /data/upload/0039/653 dc.identifier.copyno: 1 dc.identifier.uri: http://www.new.dli.ernet.in/handle/2015/167604 dc.description.numberedpages: 88 dc.description.numberedpages: 16 dc.description.scanningcentre: RMSC, IIIT-H dc.description.main: 1 dc.description.tagged: 0 dc.description.totalpages: 104 dc.format.mimetype: application/pdf dc.language.iso: English dc.publisher.digitalrepublisher: Universal Digital Library dc.publisher: Methuen Amp Co. Ltd. dc.rights: Copyright Protected dc.title: The Structure Of Atoms

iv, 204 pages 22 cm

We consider the most accurate tests of bound state QED, precision theory of simple atoms, related to the hyperfine splitting in light hydrogen-like atoms. We discuss the HFS interval of the 1s state in muonium and positronium and of the 2s state in hydrogen, deuterium and helium-3 ion. We summarize their QED theory and pay attention to involved effects of strong interactions. We also consider recent optical measurements of the 2s HFS interval in hydrogen and deuterium.

We consider the most accurate tests of bound state QED, precision theory of simple atoms, related to the hyperfine splitting in light hydrogen-like atoms. We discuss the HFS interval of the 1s state in muonium and positronium and of the 2s state in hydrogen, deuterium and helium-3 ion. We summarize their QED theory and pay attention to involved effects of strong interactions. We also consider recent optical measurements of the 2s HFS interval in hydrogen and deuterium.

iv, 204 p. : 22 cm

iv, 204 p. : 22 cm

Lewis, Gilbert Newton Valence And The Structure Of Atoms And Molecules Lewis Gilbert Newton New York 1923

"The Structure of Atoms and the Octet Theory of Valence" is an article from Proceedings of the National Academy of Sciences of the United States of America, Volume 5 . View more articles from Proceedings of the National Academy of Sciences of the United States of America . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-84046

A cassette tape that provides the audio track to a filmstrip of the same name.  Side 1 and Side 2 contain identical content, but one may be of better quality than the other.  Side 1 is manual and Side 2 is automatic.

A book discussing various aspects of atomic and molecular structure.

This article is from F1000Research , volume 2 . Abstract Predicting the three dimensional native state structure of a protein from its primary sequence is an unsolved grand challenge in molecular biology. Two main computational approaches have evolved to obtain the structure from the protein sequence - ab initio/de novo methods and template-based modeling - both of which typically generate multiple possible native state structures. Model quality assessment programs (MQAP) validate these predicted structures in order to identify the correct native state structure. Here, we propose a MQAP for assessing the quality of protein structures based on the distances of consecutive Cα atoms. We hypothesize that the root-mean-square deviation of the distance of consecutive Cα (RDCC) atoms from the ideal value of 3.8 Å, derived from a statistical analysis of high quality protein structures (top100H database), is minimized in native structures. Based on tests with the top100H set, we propose a RDCC cutoff value of 0.012 Å, above which a structure can be filtered out as a non-native structure. We applied the RDCC discriminator on decoy sets from the Decoys 'R' Us database to show that the native structures in all decoy sets tested have RDCC below the 0.012 Å cutoff. While most decoy sets were either indistinguishable using this discriminator or had very few violations, all the decoy structures in the fisa decoy set were discriminated by applying the RDCC criterion. This highlights the physical non-viability of the fisa decoy set, and possible issues in benchmarking other methods using this set. The source code and manual is made available at https://github.com/sanchak/mqap and permanently available on 10.5281/zenodo.7134.

This article is from F1000Research , volume 2 . Abstract Predicting the three dimensional native state structure of a protein from its primary sequence is an unsolved grand challenge in molecular biology. Two main computational approaches have evolved to obtain the structure from the protein sequence - ab initio/de novo methods and template-based modeling - both of which typically generate multiple possible native state structures. Model quality assessment programs (MQAP) validate these predicted structures in order to identify the correct native state structure. Here, we propose a MQAP for assessing the quality of protein structures based on the distances of consecutive Cα atoms. We hypothesize that the root-mean-square deviation of the distance of consecutive Cα (RDCC) atoms from the ideal value of 3.8 Å, derived from a statistical analysis of high quality protein structures (top100H database), is minimized in native structures. Based on tests with the top100H set, we propose a RDCC cutoff value of 0.012 Å, above which a structure can be filtered out as a non-native structure. We applied the RDCC discriminator on decoy sets from the Decoys 'R' Us database to show that the native structures in all decoy sets tested have RDCC below the 0.012 Å cutoff. While most decoy sets were either indistinguishable using this discriminator or had very few violations, all the decoy structures in the fisa decoy set were discriminated by applying the RDCC criterion. This highlights the physical non-viability of the fisa decoy set, and possible issues in benchmarking other methods using this set. The source code and manual is made available at https://github.com/sanchak/mqap and permanently available on 10.5281/zenodo.7134.

Since the work of Anderson on localization, interference effects for the propagation of a wave in the presence of disorder have been extensively studied, as exemplified in coherent backscattering (CBS) of light. In the multiple scattering of light by a disordered sample of thermal atoms, interference effects are usually washed out by the fast atomic motion. This is no longer true for cold atoms where CBS has recently been observed. However, the internal structure of the atoms strongly influences the interference properties. In this paper, we consider light scattering by an atomic dipole transition with arbitrary degeneracy and study its impact on coherent backscattering. We show that the interference contrast is strongly reduced. Assuming a uniform statistical distribution over internal degrees of freedom, we compute analytically the single and double scattering contributions to the intensity in the weak localization regime. The so-called ladder and crossed diagrams are generalized to the case of atoms and permit to calculate enhancement factors and backscattering intensity profiles for polarized light and any closed atomic dipole transition.

We perform accurate calculations of the dependence of transition frequencies in two valence electron atoms and ions on a variation of the fine structure constant, alpha. The relativistic Hartree-Fock method is used with many-body perturbation theory and configuration interaction methods to calculate transition frequencies. The results are to be used in atomic-clock-type laboratory experiments designed to test whether alpha varies in time.

"The Structure of Atoms and the Evolution of the Elements as Related to the Composition of the Nuclei of Atoms" is an article from Science, Volume 46 . View more articles from Science . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-1643597

"The Structure of Atoms and the Evolution of the Elements as Related to the Composition of the Nuclei of Atoms" is an article from Science, Volume 46 . View more articles from Science . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-1643597

"The Structure of Atoms, and the Evolution of the Elements as Related to the Composition of the Nuclei of Atoms" is an article from Science, Volume 46 . View more articles from Science . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-1641735

The theory of QED corrections to hyperfine structure in light hydrogenic atoms and ions has recently advanced to the point that the uncertainty of these corrections is much smaller than 1 part per million (ppm), while the experiments are even more accurate. The difference of the experimental results and the corresponding QED theory is due to nuclear effects, which are primarily the result of the finite nuclear charge and magnetization distributions. This difference varies from tens to hundreds of ppm. We have calculated the dominant nuclear component of the 1s hyperfine interval for deuterium, tritium and singly ionized helium, using a unified approach with modern second-generation potentials. The calculated nuclear corrections are within 3% of the experimental values for deuterium and tritium, but are roughly 20% discrepant for helium. The nuclear corrections for the trinucleon systems can be qualitatively understood by invoking SU(4) symmetry.

5 p. l., 314 p. 21 cm

5 p. l., 314 p. 21 cm

We study the effect of parametric excitations on systems of confined ultracold Bose atoms in periodically modulated optical lattices. In the regime where Mott insulating and Superfluid domains coexist, we show that the dependence of the energy absorbed by the system on the frequency of the modulation serves as an experimental probe for the existence and properties of Mott insulating-Superfluid domains.

We study the effect of parametric excitations on systems of confined ultracold Bose atoms in periodically modulated optical lattices. In the regime where Mott insulating and Superfluid domains coexist, we show that the dependence of the energy absorbed by the system on the frequency of the modulation serves as an experimental probe for the existence and properties of Mott insulating-Superfluid domains.

We analyze second-order $M1$-$M1$ and $M1$-$E2$ effects to the hyperfine structure (HFS) of the lowest energy $P$ states of alkali-metal atoms arising from the coupling of the two ($J=1/2,3/2$) fine-structure levels through the hyperfine interaction. We find these effects to be especially sizable in Li, leading to a $9\sigma$ correction to the most accurate reported experimental value of the $A(P_{1/2})$ HFS constant of $^7$Li [D. Das and V. Natarajan, J. Phys. B \textbf{41}, 035001 (2008)]. For the remaining alkali-metal systems, the results tabulated within may be referenced as higher precision is sought in experimental determination of the HFS constants.

We report an accurate measurement of the recoil velocity of Rb atoms based on Bloch oscillations in a vertical accelerated optical lattice. We transfer about 900 recoil momenta with an efficiency of 99.97 % per recoil. A set of 72 measurements of the recoil velocity, each one with a relative uncertainty of about 33 ppb in 20 min integration time, leads to a determination of the fine structure constant alpha with a statistical relative uncertainty of 4.4 ppb. The detailed analysis of the different systematic errors yields to a relative uncertainty of 6.7 ppb. The deduced value of 1/alpha is 137.03599878(91).

Book digitized by Google from the library of the New York Public Library and uploaded to the Internet Archive by user tpb.

"The Structure of Complex Atoms and the Changes of Mass and Weight Involved in their Formation" is an article from Proceedings of the National Academy of Sciences of the United States of America, Volume 1 . View more articles from Proceedings of the National Academy of Sciences of the United States of America . View this article on JSTOR . View this article's JSTOR metadata . You may also retrieve all of this items metadata in JSON at the following URL: https://archive.org/metadata/jstor-83266

Book Source: Digital Library of India Item 2015.448991 dc.contributor.author: Kondratyev V. dc.date.accessioned: 2015-09-18T18:26:09Z dc.date.available: 2015-09-18T18:26:09Z dc.date.digitalpublicationdate: 2015 dc.identifier.other: 12028 dc.identifier.barcode: 99999990907376 dc.identifier.origpath: /data58/upload/0109/093 dc.identifier.copyno: 1 dc.identifier.uri: http://www.new.dli.ernet.in/handle/2015/448991 dc.description.scannerno: 6 dc.description.scanningcentre: Allama Iqbal Library, University of Kashmir dc.description.main: 1 dc.description.tagged: 0 dc.description.totalpages: 532 dc.format.mimetype: application/pdf dc.language.iso: English dc.publisher.digitalrepublisher: Digital Library Of India dc.publisher: Foreign Languages Publishing House, Moscow dc.rights: Not Available dc.source.library: Womens College, M. A Road Srinagar dc.subject.classification: Natural Sciences dc.subject.classification: Physics dc.title: The Structure Of Atoms And Molecules dc.type: Print - Paper dc.type: Book

Book Source: Digital Library of India Item 2015.448991 dc.contributor.author: Kondratyev V. dc.date.accessioned: 2015-09-18T18:26:09Z dc.date.available: 2015-09-18T18:26:09Z dc.date.digitalpublicationdate: 2015 dc.identifier.other: 12028 dc.identifier.barcode: 99999990907376 dc.identifier.origpath: /data58/upload/0109/093 dc.identifier.copyno: 1 dc.identifier.uri: http://www.new.dli.ernet.in/handle/2015/448991 dc.description.scannerno: 6 dc.description.scanningcentre: Allama Iqbal Library, University of Kashmir dc.description.main: 1 dc.description.tagged: 0 dc.description.totalpages: 532 dc.format.mimetype: application/pdf dc.language.iso: English dc.publisher.digitalrepublisher: Digital Library Of India dc.publisher: Foreign Languages Publishing House, Moscow dc.rights: Not Available dc.source.library: Womens College, M. A Road Srinagar dc.subject.classification: Natural Sciences dc.subject.classification: Physics dc.title: The Structure Of Atoms And Molecules dc.type: Print - Paper dc.type: Book

The theory of nucleation of nanoscale structures of the adsorbed atoms (adatoms), which occurs as a result of the self-consistent interaction of adatoms with the surface acoustic wave and electronic subsystem is developed. Temperature regimes of formation of nanoclusters on ${n}$-GaAs surface under the action of laser irradiation are investigated. The offered model permits to choose optimal technological parameters (temperature, doping degree, intensity of laser irradiation) for the formation of the surface periodic defect-deformation structures under the action of laser irradiation.

The theory of nucleation of nanoscale structures of the adsorbed atoms (adatoms), which occurs as a result of the self-consistent interaction of adatoms with the surface acoustic wave and electronic subsystem is developed. Temperature regimes of formation of nanoclusters on ${n}$-GaAs surface under the action of laser irradiation are investigated. The offered model permits to choose optimal technological parameters (temperature, doping degree, intensity of laser irradiation) for the formation of the surface periodic defect-deformation structures under the action of laser irradiation.

We have measured hyperfine structure in the first-excited $P$ state ($D$ lines) of all the naturally-occurring alkali atoms. We use high-resolution laser spectroscopy to resolve hyperfine transitions, and measure intervals by locking the frequency shift produced by an acousto-optic modulator to the difference between two transitions. In most cases, the hyperfine coupling constants derived from our measurements improve previous values significantly.