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Full-Text Articles in Physics
Temperature Tides Across The Mid-Latitude Summer Turbopause Measured By A Sodium Lidar And Mighti/Icon, Tao Yuan, M. H. Stevens, C. R. Englert, T. J. Immel
Temperature Tides Across The Mid-Latitude Summer Turbopause Measured By A Sodium Lidar And Mighti/Icon, Tao Yuan, M. H. Stevens, C. R. Englert, T. J. Immel
All Physics Faculty Publications
Local full diurnal coverage of temperature variations across the turbopause (∼90–115 km altitude) is achieved by combining the nocturnal observations of a Sodium (Na) Doppler lidar on the Utah State University (USU) campus (41.7°N, 248.2°E) and NASA Michelson interferometer for global high-resolution thermospheric imaging (MIGHTI)/Ionospheric connection explorer (ICON) daytime observations made in the same vicinity. In this study, utilizing this hybrid data set during summer 2020 between June 12th and July 15th, we retrieve the temperature signatures of diurnal and semidiurnal tides in this region. The tidal amplitudes of both components have similar vertical variation with increasing altitude: less than …
Sodium Lidar For Mesopause Temperature And Wind Studies, Xiaoqi Xi
Sodium Lidar For Mesopause Temperature And Wind Studies, Xiaoqi Xi
Physics Capstone Projects
In 1990 Dr. Chiao-Yao She developed a narrowband Na Temperature lidar in Colorado State University (CSU), it immediately became an important instrument to measure the temperature in mesopause region (80-105 km in altitude): the atmospheric layer between mesosphere and thermosphere [Krueger et al., 2015]. Led by Dr. Tao Yuan, this system was relocated to Utah State University (USU) in summer 2010 and has been continuing its exploration of upper atmosphere. This report will give a brief introduction to the theory and application of Sodium Lidar.
The Density Broadening In A Sodium F=2 Condensate Detected By A Pulse Train, Jianing Han
The Density Broadening In A Sodium F=2 Condensate Detected By A Pulse Train, Jianing Han
Physics Faculty Scholarship
The dipole-blockaded sodiumclock transition has been detected by high resolution microwave spectroscopy, the multiple-pulse spectroscopy. This spectroscopic technique has been first used to detect the density broadening and shifting in a Sodium Bose Einstein Condensate (BEC) by probing the sodium clock-transition. Moreover, by narrowing the pulse-width of the pulses, some of the broadening mechanisms can be partially reduced. The results reported here are essential steps toward the ground-statequantum computing, few-body spectroscopy, spin squeezing and quantum metrology.
A Global Climatology Of The Mesospheric Sodium Layerfrom Gomos Data During The 2002-2008 Period, D. F. Fussen, F. Vanhellemont, C. T'Etart, N. Mateshvili, E. Dekemper, N. Loodts, C. Bingen, E. Kyrola, J. Tamminen, V. Sofieva, A. Hauchecorne, F. Dalaudier, J. L. Bertaux, G. Barrot, L. Blanot, O. Fanton D'Andon, T. Fehr, L. Saavedra, Tao Yuan, C. Y. She
A Global Climatology Of The Mesospheric Sodium Layerfrom Gomos Data During The 2002-2008 Period, D. F. Fussen, F. Vanhellemont, C. T'Etart, N. Mateshvili, E. Dekemper, N. Loodts, C. Bingen, E. Kyrola, J. Tamminen, V. Sofieva, A. Hauchecorne, F. Dalaudier, J. L. Bertaux, G. Barrot, L. Blanot, O. Fanton D'Andon, T. Fehr, L. Saavedra, Tao Yuan, C. Y. She
All Physics Faculty Publications
This paper presents a climatology of the mesospheric sodium layer built from the processing of 7 years of GOMOS data. With respect to preliminary results already published for the year 2003, a more careful analysis was applied to the averaging of occultations inside the climatological bins (10° in latitude-1 month). Also, the slant path absorption lines of the Na doublet around 589 nm shows evidence of partial saturation that was responsible for an underestimation of the Na concentration in our previous results. The sodium climatology has been validated with respect to the Fort Collins lidar measurements and, to a lesser …
Sodium And Potassiumvapor Faraday Filters Re-Visited: Theory And Applications, S. D. Harrell, C. Y. She, Tao Yuan, D. A. Krueger, H. Chen, S. Chen, Z. L. Hu
Sodium And Potassiumvapor Faraday Filters Re-Visited: Theory And Applications, S. D. Harrell, C. Y. She, Tao Yuan, D. A. Krueger, H. Chen, S. Chen, Z. L. Hu
All Physics Faculty Publications
A complete theory describing the transmission of atomic vapor Faraday filters is developed. The dependence of the filter transmission on atomic density and external magnetic field strength, as well as the frequency dependence of transmission, are explained in physical terms. As examples, applications of the computed results to ongoing research to suppress sky background, thus allowing Na lidar operation under sunlit conditions, and to enable measurement of the density of mesospheric oxygen atoms are briefly discussed.
Concurrent Ohimager And Sodium Temperature/Wind Lidar Observation Of Localized Ripples Over Northern Colorado, L. Tao, C. Y. She, B. P. Williams, Tao Yuan, R. L. Collins, L. Kieffabar, A. Peterson
Concurrent Ohimager And Sodium Temperature/Wind Lidar Observation Of Localized Ripples Over Northern Colorado, L. Tao, C. Y. She, B. P. Williams, Tao Yuan, R. L. Collins, L. Kieffabar, A. Peterson
All Physics Faculty Publications
On 3 and 5 September 2002 the OH all-sky imager at Platteville, Colorado (40.2°N, 104.7°W), observed small-scale, wavelike patterns (known as ripples), with horizontal wavelengths of ∼9 km and ∼7 km and lifetimes of ∼9 min and ∼15 min, respectively. The Colorado State University sodium lidar at nearby Fort Collins, Colorado (40.6°N, 105°W), also made concurrent observations of temperature and zonal and meridional winds, which allowed us to determine the nature of the ripples observed. Our observations suggest that the 3 September ripple was induced by a convective instability located at 87.5 km and the 5 September ripple was induced …
Concurrent Oh Imager And Sodiumtemperature/Wind Lidar Observation Of A Mesopause Region Undular Bore Event Over Fort Collins/Platteville, Co, C. Y. She, T. Li, B. P. Williams, Tao Yuan, R. H. Picard
Concurrent Oh Imager And Sodiumtemperature/Wind Lidar Observation Of A Mesopause Region Undular Bore Event Over Fort Collins/Platteville, Co, C. Y. She, T. Li, B. P. Williams, Tao Yuan, R. H. Picard
All Physics Faculty Publications
We reported the observation of a mesospheric front with the properties of an undular bore by an OH imager, over the Fort Collins/Platteville area on 6/7 October 2002. Unlike the earlier bore observations, a Na lidar capable of measuring mesopause region temperature, zonal, and meridional winds was in operation concurrently. The lidar data confirm, for the first time, the existence of a collocated temperature inversion layer to serve as the ducting region for bore propagation, as required by the simple theory proposed by Dewan and Picard 6 years ago. In addition, the lidar data in principle provide sufficient information for …
Spectroscopy Of Atoms Confined To The Single Node Of A Standing Wave In A Parallel-Plate Cavity, V. Sandoghar, C. I. Sukenik, S. Haroche, E. A. Hinds
Spectroscopy Of Atoms Confined To The Single Node Of A Standing Wave In A Parallel-Plate Cavity, V. Sandoghar, C. I. Sukenik, S. Haroche, E. A. Hinds
Physics Faculty Publications
We have performed spectroscopy on sodium atoms that are optically channeled in the single node of a laser standing wave set up across a parallel-plate cavity. Using this technique we have extended our previous measurement of the Lennard-Jones van der Waals energy-level shift [Sandoghdar et al., Phys. Rev. Lett. 68, 3432 (1992)] down to a cavity width of ~500 nm. We discuss the applications of this technique to the precise measurement of atom-surface distances.
A Theoretical Investigation Of The Geometries, Vibrational Frequencies, And Binding Energies Of Several Alkali Halide Dimers, Robert P. Dickey '93, David Maurice '91, Robert J. Cave, Richard J. Mawhorter
A Theoretical Investigation Of The Geometries, Vibrational Frequencies, And Binding Energies Of Several Alkali Halide Dimers, Robert P. Dickey '93, David Maurice '91, Robert J. Cave, Richard J. Mawhorter
All HMC Faculty Publications and Research
Results are presented from ab initio calculations on the symmetrical alkali halide dimers made up of Li, Na, K, F, and Cl. We examine the sensitivity of representative monomer and dimer geometries to the variation of the basis set with and without polarization and diffuse functions. The geometries are then compared with available experimental results. We have also calculated vibrational frequencies at the restricted Hartree–Fock level and examined the changes in geometry brought about by correlation using second‐order Møller–Plesset perturbation theory. It is found that Hartree–Fock theory in a modest basis set with diffuse and polarization functions yields results comparable …
Measurement Of The Casimir-Polder Force, C. I. Sukenik, M. G. Boshier, S. Cho, V. Sandoghdar, E. A. Hinds
Measurement Of The Casimir-Polder Force, C. I. Sukenik, M. G. Boshier, S. Cho, V. Sandoghdar, E. A. Hinds
Physics Faculty Publications
The authors have studied the deflection of ground-state sodium atoms passing through a micron-sized parallel-plate cavity by measuring the intensity of a sodium atomic beam transmitted through the cavity as a function of cavity plate separation. This experiment provides clear evidence for the existence of the Casimir-Polder force, which is due to modification of the ground-state Lamb shift in the confined space of a cavity. The results confirm the magnitude of the force and the distance dependence predicted by quantum electrodynamics.
Direct Measurement Of The Van Der Waals Interaction Between An Atom And Its Images In A Micron-Sized Cavity, V. Sandoghdar, C. I. Sukenik, E. A. Hinds, S. Haroche
Direct Measurement Of The Van Der Waals Interaction Between An Atom And Its Images In A Micron-Sized Cavity, V. Sandoghdar, C. I. Sukenik, E. A. Hinds, S. Haroche
Physics Faculty Publications
The authors have measured by laser spectroscopy the energy of interaction between a sodium atom and its images in the walls of a micron-sized cavity. This cavity-QED study is the first direct quantitative test of the Lennard-Jones van der Waals interaction as a function of controlled atom-surface separation and mean-square electric dipole moment.
Enhanced Vibrational Broadening Of Core-Level Photoemission From The Surface Of Na(110), D. Mark Riffe, G. K. Wertheim, P. H. Citrin
Enhanced Vibrational Broadening Of Core-Level Photoemission From The Surface Of Na(110), D. Mark Riffe, G. K. Wertheim, P. H. Citrin
All Physics Faculty Publications
High-resolution temperature-dependent photoemission data from Na 2p core levels reveal substantially larger phonon broadening in the first atomic layer of Na(110) than in the bulk. We show that the enhanced width is due primarily to the excitation of relatively soft phonon modes perpendicular to the surface. Soft surface-phonon modes also account for previously reported but uninterpreted broadening of transition-metal surface-atom core levels.
Differential, Partial Cross Sections For Electron Excitation Of The Sodium 3p State, Xianming Han, G. W. Schwinn, A. Gallagher
Differential, Partial Cross Sections For Electron Excitation Of The Sodium 3p State, Xianming Han, G. W. Schwinn, A. Gallagher
Scholarship and Professional Work - LAS
Using a powerful laser-based experimental method, the cross section for electron excitation of Na(3S) atoms to the Na(3P) state has been decomposed into partial components with respect to changes in the spin and angular momentum of the atomic electron, and these partial cross sections are further reduced to their differential character with respect to the electron scattering angle. Partial, differential cross sections are reported for electron collision energies from threshold 2.1 to 3.6 eV, and compared to available calculations.
Path Integral Study Of The Correlated Electronic States Of Na4–Na6, Randall W. Hall
Path Integral Study Of The Correlated Electronic States Of Na4–Na6, Randall W. Hall
Collected Faculty and Staff Scholarship
Feynman’s path integral formulation of quantum mechanics is used to study the correlated electronic states of Na4–Na6. Two types of simulations are performed: in the first, the nuclei are allowed to move at finite temperature in order to find the most stable geometries. In agreement with previous calculations, we find that planar structures are the most stable and that there is significant vibrational amplitude at finite temperatures, indicating that the Born–Oppenheimer surface is relatively flat. In the second type of simulation, the nuclei are held fixed at symmetric and asymmetric geometries and the correlated electron density is found. Our results …
The Treatment Of Exchange In Path Integral Simulations Via An Approximate Pseudopotential, Randall W. Hall
The Treatment Of Exchange In Path Integral Simulations Via An Approximate Pseudopotential, Randall W. Hall
Collected Faculty and Staff Scholarship
An approximate form that includes the effects of exchange is suggested for the short time propagator used in path integral simulations. The form is inspired physically by the approximation made in Hartree–Fock treatments of atoms and molecules. The approximate propagator is used with q u a n t i t a t i v e accuracy in two systems: an ideal gas of fermions localized in a three‐dimensional harmonic well and the triplet state of the sodium dimer.
Experimental Fine-Structure Branching Ratios For Na-Rare-Gas Optical Collisions, Mark D. Havey, F. T. Delahanty, Linda L. Vahala, Gary E. Copeland
Experimental Fine-Structure Branching Ratios For Na-Rare-Gas Optical Collisions, Mark D. Havey, F. T. Delahanty, Linda L. Vahala, Gary E. Copeland
Electrical & Computer Engineering Faculty Publications
Experimental ratios for branching into the fine-structure levels of the Na 3p multiplet, as a consequence of an optical collision with He, Ne, Ar, Kr, or Xe, are reported. The process studied is Na(3s2S1/2)+R+nhNNa(3p2Pj)+R+(n-1)hN, where R represents a rare-gas atom and where the laser frequency N is tuned in the wings of the Na resonance transitions. The branching ratios are defined as I(D1)/I(D2) where I(D1) and I(D2) are measured intensities of the atomic Na D1 and D2 lines. The ratios are determined for detunings ranging from about 650 …
Nonadiabatic Theory Of Fine-Structure Branching Cross Sections For Na-He, Na-Ne, And Na-Ar Optical Collisions, Linda L. Vahala, P. S. Julienne, Mark D. Havey
Nonadiabatic Theory Of Fine-Structure Branching Cross Sections For Na-He, Na-Ne, And Na-Ar Optical Collisions, Linda L. Vahala, P. S. Julienne, Mark D. Havey
Electrical & Computer Engineering Faculty Publications
The nonadiabatic close-coupled theory of atomic collisions in a radiation field is generalized to include electron spin and is used to consider the weak-field Na–rare-gas (RG) optical collision Na(2S1/2)+RG+nhν μNa(2Pj)+RG+(n-1)hν. The effects of detuning and incident energy on the branching into the atomic Na 3p2P3/2 and 3p2P1/2 states are examined. The cross sections σ(j) are found to have a strong asymmetry between red and blue detuning as well as a complex threshold and resonance structure dependence on energy. A partial cross-section analysis …