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Articles 1  30 of 67
FullText Articles in Physical Sciences and Mathematics
Enhanced Piezoresponse And Nonlinear Optical Properties Of Fluorinated SelfAssembled Peptide Nanotubes, Soma Khanra, Sandra V. Vassiliades, Wendel A. Alves, Kaidi Yang, Rainer Glaser, Kartik Ghosh, Payal Bhattacharya, Ping Yu, Suchismita Guha
Enhanced Piezoresponse And Nonlinear Optical Properties Of Fluorinated SelfAssembled Peptide Nanotubes, Soma Khanra, Sandra V. Vassiliades, Wendel A. Alves, Kaidi Yang, Rainer Glaser, Kartik Ghosh, Payal Bhattacharya, Ping Yu, Suchismita Guha
Chemistry Faculty Research & Creative Works
Selfassembled L,Ldiphenylalanine (FF) nanostructures offer an attractive platform for photonics and nonlinear optics. The nonlinear optical (NLO) coefficients of FF nanotubes depend on the diameter of the tube [S. Khanra et al. Phys. Chem. Chem. Phys. 19(4), 30843093 (2017)]. To further enhance the NLO properties of FF, we search for structural modifications. Here, we report on the synthesis of fluorinated FF dipeptides by replacing one orthohydrogen atom in each of the phenyl groups of FF by a fluorine atom. Densityfunctional theoretical calculations yield insights into minimum energy conformers of fluorinated FF (FlFF). FlFF selfassembles akin to FF into ...
Atoms In Quasilocal Integral Domains, Kevin Wilson Bombardier
Atoms In Quasilocal Integral Domains, Kevin Wilson Bombardier
Theses and Dissertations
Let R be an integral domain. An atom is a nonzero nonunit x of R where x = yz implies that either y or z is a unit. We say that R is an atomic domain if each nonzero nonunit is a finite product of atoms. An atomic domain with only finitely many nonassociate atoms is called a CohenKaplansky (CK) domain. We will investigate atoms in integral domains R with a unique maximal ideal M. Of particular interest will be atoms that are not in M^2.
After studying the atoms in integral domains, we will narrow our focus to CK ...
Resonance Strengths For Kll Dielectronic Recombination Of Highly Charged Mercury Ions And Improved Empirical Z Scaling Law, Zoltan Harman, Chintan Shah, Antonio J. Gonzalez Martinez, Ulrich D. Jentschura, For Full List Of Authors, See Publisher's Website.
Resonance Strengths For Kll Dielectronic Recombination Of Highly Charged Mercury Ions And Improved Empirical Z Scaling Law, Zoltan Harman, Chintan Shah, Antonio J. Gonzalez Martinez, Ulrich D. Jentschura, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
Theoretical and experimental resonance strengths for KLL dielectronic recombination (DR) into He, Li, Be, and Blike mercury ions are presented, based on stateresolved DR xray spectra recorded at the Heidelberg electronbeam ion trap. The DR resonance strengths are experimentally extracted by normalizing them to simultaneously recorded radiative recombination signals. The results are compared to stateoftheart atomic calculations that include relativistic electron correlation and configuration mixing effects. Combining the present data with other existing ones, we derive an improved semiempirical Zscaling law for DR resonance strengths as a function of the atomic number, taking into account higherorder relativistic corrections, which are ...
AllOptical Atom Trap As A Target For MotrimsLike Collision Experiments, S. Sharma, B. P. Acharya, Daniel Fischer, For Full List Of Authors, See Publisher's Website.
AllOptical Atom Trap As A Target For MotrimsLike Collision Experiments, S. Sharma, B. P. Acharya, Daniel Fischer, For Full List Of Authors, See Publisher's Website.
Physics Faculty Research & Creative Works
Momentumresolved scattering experiments with lasercooled atomic targets have been performed since almost two decades with magnetooptical trap recoil ion momentum spectroscopy (MOTRIMS) setups. Compared to experiments with gasjet targets, MOTRIMS features significantly lower target temperatures allowing for an excellent recoil ion momentum resolution. However, the coincident and momentumresolved detection of electrons was long rendered impossible due to incompatible magnetic field requirements. Here we report on an experimental approach which is based on an alloptical ^{6}Liatom trap thatin contrast to magnetooptical trapsdoes not require magnetic field gradients in the trapping region. Atom temperatures of about 2 mK and number densities ...
LongRange Interactions Of Hydrogen Atoms In Excited States. Iii. Ns−1s Interactions For N ≥ 3, Chandra M. Adhikari, V. Debierre, Ulrich D. Jentschura
LongRange Interactions Of Hydrogen Atoms In Excited States. Iii. Ns−1s Interactions For N ≥ 3, Chandra M. Adhikari, V. Debierre, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
The longrange interaction of excited neutral atoms has a number of interesting and surprising properties such as the prevalence of longrange oscillatory tails and the emergence of numerically large van der Waals C_{6} coefficients. Furthermore, the energetically quasidegenerate nP states require special attention and lead to mathematical subtleties. Here we analyze the interaction of excited hydrogen atoms in nS states (3 ≤ n ≤ 12) with groundstate hydrogen atoms and find that the C6 coefficients roughly grow with the fourth power of the principal quantum number and can reach values in excess of 240000 (in atomic units) for states with n ...
ElectronImpact Ionization Of LaserAligned Atoms  Contributions From Both Natural And UnnaturalParity States, Andrew James Murray, James Colgan, Don H. Madison, Matthew Harvey, Ahmad Sakaamini
ElectronImpact Ionization Of LaserAligned Atoms  Contributions From Both Natural And UnnaturalParity States, Andrew James Murray, James Colgan, Don H. Madison, Matthew Harvey, Ahmad Sakaamini
Physics Faculty Research & Creative Works
Synopsis. The progress of experimental and theoretical measurements for (e,2e) ionization cross sections from laseraligned atoms is presented here. It is found that both natural and unnatural parity contributions must be included in the models to emulate the experimental data.
Natural & UnnaturalParity Contributions In ElectronImpact Ionization Of LaserAligned Atoms, Andrew James Murray, James Colgan, Don H. Madison, Matthew Harvey, Ahmad Sakaamini, James Pursehouse, Kate Nixon, Al Stauffer
Natural & UnnaturalParity Contributions In ElectronImpact Ionization Of LaserAligned Atoms, Andrew James Murray, James Colgan, Don H. Madison, Matthew Harvey, Ahmad Sakaamini, James Pursehouse, Kate Nixon, Al Stauffer
Physics Faculty Research & Creative Works
Differential cross section measurements from laseraligned Mg atoms are compared to theoretical calculations using both time dependent and timeindependent formalisms. It is found that both natural and unnatural parity contributions to the calculated cross sections are required to emulate the data when the state is aligned out of the scattering plane.
LongRange Tails In Van Der Waals Interactions Of ExcitedState And GroundState Atoms, Ulrich D. Jentschura, V. Debierre
LongRange Tails In Van Der Waals Interactions Of ExcitedState And GroundState Atoms, Ulrich D. Jentschura, V. Debierre
Physics Faculty Research & Creative Works
A quantum electrodynamic calculation of the interaction of an excitedstate atom with a groundstate atom is performed. For an excited reference state and a lowerlying virtual state, the contribution to the interaction energy naturally splits into a pole term and a Wickrotated term. The pole term is shown to dominate in the longrange limit, altering the functional form of the interaction from the retarded 1/R^{7} CasimirPolder form to a longrange tail  provided by the Wickrotated term  proportional to cos[2(E_{m}  E_{n})R/(ħc)]/R^{2}, where E_{m} < E_{n} is the energy of a virtual ...
Virtual Resonant Emission And Oscillatory LongRange Tails In Van Der Waals Interactions Of Excited States: Qedtreatment And Applications, Ulrich D. Jentschura, Chandra Mani Adhikari, Vincent Debierre
Virtual Resonant Emission And Oscillatory LongRange Tails In Van Der Waals Interactions Of Excited States: Qedtreatment And Applications, Ulrich D. Jentschura, Chandra Mani Adhikari, Vincent Debierre
Physics Faculty Research & Creative Works
We report on a quantum electrodynamic (QED) investigation of the interaction between a ground state atom with another atom in an excited state. General expressions, applicable to any atom, are indicated for the longrange tails that are due to virtual resonant emission and absorption into and from vacuum modes whose frequency equals the transition frequency to available lowerlying atomic states. For identical atoms, one of which is in an excited state, we also discuss the mixing term that depends on the symmetry of the twoatom wave function (these evolve into either the gerade or the ungerade state for close approach ...
LongRange Interactions Of Hydrogen Atoms In Excited States. Ii. HyperfineResolved 2s2s Systems, Ulrich D. Jentschura, Vincent Debierre, Chandra Mani Adhikari, Arthur N. Matveev, Nikolai N. Kolachevsky
LongRange Interactions Of Hydrogen Atoms In Excited States. Ii. HyperfineResolved 2s2s Systems, Ulrich D. Jentschura, Vincent Debierre, Chandra Mani Adhikari, Arthur N. Matveev, Nikolai N. Kolachevsky
Physics Faculty Research & Creative Works
The interaction of two excited hydrogen atoms in metastable states constitutes a theoretically interesting problem because of the quasidegenerate 2P_{1/2} levels that are removed from the 2S states only by the Lamb shift. The total Hamiltonian of the system is composed of the van der Waals Hamiltonian, the Lamb shift, and the hyperfine effects. The van der Waals shift becomes commensurate with the 2S2P_{3/2} finestructure splitting only for close approach (R < 100a_{0}, where a_{0} is the Bohr radius) and one may thus restrict the discussion to the levels with n = 2 and J = 1/2 ...
LongRange Interactions Of Hydrogen Atoms In Excited States. I. 2s1s Interactions And DiracΔ Perturbations, Chandra Mani Adhikari, Vincent Debierre, Arthur N. Matveev, Nikolai N. Kolachevsky, Ulrich D. Jentschura
LongRange Interactions Of Hydrogen Atoms In Excited States. I. 2s1s Interactions And DiracΔ Perturbations, Chandra Mani Adhikari, Vincent Debierre, Arthur N. Matveev, Nikolai N. Kolachevsky, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
The theory of the longrange interaction of metastable excited atomic states with groundstate atoms is analyzed. We show that the longrange interaction is essentially modified when quasidegenerate states are available for virtual transitions. A discrepancy in the literature regarding the van der Waals coefficient C_{6} (2S ;1 S ) describing the interaction of metastable atomic hydrogen ( 2 S state) with a groundstate hydrogen atom is resolved. In the the van der Waals range a_{0} ≪ R ≪ a_{0} / α , where a_{0} = ℏ / α m c is the Bohr radius and α is the finestructure constant, one finds the symmetrydependent result ...
Determination Of Interstellar O Parameters Using The First Two Years Of Data From The Interstellar Boundary Explorer, N. A. Schwadron, E. Möbius, D. J. Mccomas, P. Bochsler, M. Bzowski, S. A. Fuselier, G. Livadiotis, P. Frisch, H. R. Müller, D. Heirtzler, H. Kucharek, M. A. Lee
Determination Of Interstellar O Parameters Using The First Two Years Of Data From The Interstellar Boundary Explorer, N. A. Schwadron, E. Möbius, D. J. Mccomas, P. Bochsler, M. Bzowski, S. A. Fuselier, G. Livadiotis, P. Frisch, H. R. Müller, D. Heirtzler, H. Kucharek, M. A. Lee
Open Dartmouth: Peerreviewed articles by Dartmouth faculty
The direct measurements of interstellar matter by the Interstellar Boundary Explorer ( IBEX ) mission have opened a new and important chapter in our study of the interactions that control the boundaries of our heliosphere. Here we derive for the quantitative information about interstellar O flow parameters from IBEX lowenergy neutral atom data for the first time. Specifically, we derive a relatively narrow fourdimensional parameter tube along which interstellar O flow parameters must lie. Along the parameter tube, we find a large uncertainty in interstellar O flow longitude, 76°.0 ± 3°.4 from χ 2 analysis and 76°.5 ± 6°.2 from ...
Theory Of Noncontact Friction For AtomSurface Interactions, Ulrich D. Jentschura, M. Janke, Maarten F M De Kieviet
Theory Of Noncontact Friction For AtomSurface Interactions, Ulrich D. Jentschura, M. Janke, Maarten F M De Kieviet
Physics Faculty Research & Creative Works
The noncontact (van der Waals) friction is an interesting physical effect, which has been the subject of controversial scientific discussion. The direct friction term due to the thermal fluctuations of the electromagnetic field leads to a friction force proportional to 1/Z^{5} (where Z is the atomwall distance). The backaction friction term takes into account the feedback of thermal fluctuations of the atomic dipole moment onto the motion of the atom and scales as 1/Z^{8}. We investigate noncontact friction effects for the interactions of hydrogen, groundstate helium, and metastable helium atoms with αquartz (SiO_{2}), gold (Au ...
Analytical Model For Calibrating Laser Intensity In StrongFieldIonization Experiments, SongFeng. Zhao, AnhThu Le, Cheng Jin, Xu Wang, C. D. Lin
Analytical Model For Calibrating Laser Intensity In StrongFieldIonization Experiments, SongFeng. Zhao, AnhThu Le, Cheng Jin, Xu Wang, C. D. Lin
Physics Faculty Research & Creative Works
The interaction of an intense laser pulse with atoms and molecules depends extremely nonlinearly on the laser intensity. Yet experimentally there still exists no simple reliable methods for determining the peak laser intensity within the focused volume. Here we present a simple method, based on an improved PerelomovPopovTerent'ev model, that would allow the calibration of laser intensities from the measured ionization signals of atoms or molecules. The model is first examined by comparing ionization probabilities (or signals) of atoms and several simple diatomic molecules with those from solving the timedependent Schrödinger equation. We then show the possibility of using ...
FewBoson Processes In The Presence Of An Attractive Impurity Under OneDimensional Confinement, Nirav Mehta, Connor Morehead
FewBoson Processes In The Presence Of An Attractive Impurity Under OneDimensional Confinement, Nirav Mehta, Connor Morehead
Nirav P Mehta
We consider a fewboson system confined to one dimension with a single distinguishable particle of lesser mass. All particle interactions are modeled with δ functions, but due to the mass imbalance the problem is nonintegrable. Universal fewbody binding energies, atomdimer and atomtrimer scattering lengths, are all calculated in terms of two parameters, namely the mass ratio mL/mH, and ratio gHH/gHL of the δfunction couplings. We specifically identify the values of these ratios for which the atomdimer or atomtrimer scattering lengths vanish or diverge. We identify regions in this parameter space in which various fewbody inelastic processes become energetically ...
EnergyEfficient Computational Chemistry: Comparison Of X86 And Arm Systems, Kristopher Keipert, Gaurav Mitra, Vaibhav Sunriyal, Sarom S. Leang, Masha Sosonkina, Alistair P. Rendell, Mark S. Gordon
EnergyEfficient Computational Chemistry: Comparison Of X86 And Arm Systems, Kristopher Keipert, Gaurav Mitra, Vaibhav Sunriyal, Sarom S. Leang, Masha Sosonkina, Alistair P. Rendell, Mark S. Gordon
Computational Modeling and Simulation Engineering Faculty Publications
The computational efficiency and energytosolution of several applications using the GAMESS quantum chemistry suite of codes is evaluated for 32bit and 64bit ARMbased computers, and compared to an x86 machine. The x86 system completes all benchmark computations more quickly than either ARM system and is the best choice to minimize time to solution. The ARM64 and ARM32 computational performances are similar to each other for HartreeFock and density functional theory energy calculations. However, for memoryintensive secondorder perturbation theory energy and gradient computations the lower ARM32 read/write memory bandwidth results in computation times as much as 86% longer than on ...
FewBoson Processes In The Presence Of An Attractive Impurity Under OneDimensional Confinement, Nirav P. Mehta, Connor D. Morehead
FewBoson Processes In The Presence Of An Attractive Impurity Under OneDimensional Confinement, Nirav P. Mehta, Connor D. Morehead
Physics and Astronomy Faculty Research
We consider a fewboson system confined to one dimension with a single distinguishable particle of lesser mass. All particle interactions are modeled with δ functions, but due to the mass imbalance the problem is nonintegrable. Universal fewbody binding energies, atomdimer and atomtrimer scattering lengths, are all calculated in terms of two parameters, namely the mass ratio m_{L}/m_{H}, and ratio g_{HH}/g_{HL} of the δfunction couplings. We specifically identify the values of these ratios for which the atomdimer or atomtrimer scattering lengths vanish or diverge. We identify regions in this parameter space in which various ...
Exploring The Possibility Of O And Ne Contamination In Ulysses Observations Of Interstellar Helium, Brian E. Wood, HansReinhard Müller, Maciej Bzowski, Justyna M. Sokół
Exploring The Possibility Of O And Ne Contamination In Ulysses Observations Of Interstellar Helium, Brian E. Wood, HansReinhard Müller, Maciej Bzowski, Justyna M. Sokół
Open Dartmouth: Peerreviewed articles by Dartmouth faculty
We explore the possibility that interstellar O and Ne may be contributing to the particle signal from the GAS instrument on Ulysses, which is generally assumed to be entirely He. Motivating this study is the recognition that an interstellar temperature higher than any previously estimated from Ulysses data could potentially resolve a discrepancy between Ulysses He measurements and those from the Interstellar Boundary Explorer (IBEX). Contamination by O and Ne could lead to Ulysses temperature measurements that are too low. We estimate the degree of O and Ne contamination necessary to increase the inferred Ulysses temperature to 8500 K, which ...
LowEnergy (E₀ = 65 Ev) ElectronImpact Ionization Of Neon: Internormalized TripleDifferentical Cross Sections In 3d Kinematics, Xueguang Ren, Sadek M. Amami, Oleg I. Zatsarinny, Thomas Pfluger, Marvin Weyland, Woon Yong Baek, Hans Rabus, Klaus Bartschat, Don H. Madison, Alexander Dorn
LowEnergy (E₀ = 65 Ev) ElectronImpact Ionization Of Neon: Internormalized TripleDifferentical Cross Sections In 3d Kinematics, Xueguang Ren, Sadek M. Amami, Oleg I. Zatsarinny, Thomas Pfluger, Marvin Weyland, Woon Yong Baek, Hans Rabus, Klaus Bartschat, Don H. Madison, Alexander Dorn
Physics Faculty Research & Creative Works
We present a combined experimental and theoretical study on the lowenergy (E_{0} = 65 eV) electron impact ionization of neon. The experimental data are compared to predictions from a hybrid secondorder distortedwave Born plus Rmatrix approach (DWB2RM), the distortedwave Born approximation with inclusion of postcollision interaction (DWBAPCI), a threebody distortedwave approach (3DW), and a Bspline Rmatrix (BSR) with pseudostates approach. Excellent agreement is found between experiment and the 3DW and BSR theories. The importance of PCI effects is clearly visible in this lowenergy electronimpact ionization process.
Evidence For UnnaturalParity Contributions To ElectronImpact Ionization Of LaserAligned Atoms, G. S. J. Armstrong, J. Colgan, M. S. Pindzola, S. Amami, Don H. Madison, J. Pursehouse, K. L. Nixon, A. J. Murray
Evidence For UnnaturalParity Contributions To ElectronImpact Ionization Of LaserAligned Atoms, G. S. J. Armstrong, J. Colgan, M. S. Pindzola, S. Amami, Don H. Madison, J. Pursehouse, K. L. Nixon, A. J. Murray
Physics Faculty Research & Creative Works
Recent measurements have examined the electronimpact ionization of excitedstate laseraligned Mg atoms. In this work we show that the ionization cross section arising from the geometry where the aligned atom is perpendicular to the scattering plane directly probes the unnatural parity contributions to the ionization amplitude. The contributions from natural parity partial waves cancel exactly in this geometry. Our calculations resolve the discrepancy between the nonzero measured cross sections in this plane and the zero cross section predicted by distortedwave approaches. We demonstrate that this is a general feature of ionization from pstate targets by additional studies of ionization from ...
Coplanar Asymmetric Angles And Symmetric Energy Sharing Triple Differential Cross Sections For 200 Ev ElectronImpact Ionization Of Ar (3p), Zehra Nur Ozer, Sadek M. Amami, Onur Varol, Murat Yavuz, Mevlut Dogan, Don H. Madison
Coplanar Asymmetric Angles And Symmetric Energy Sharing Triple Differential Cross Sections For 200 Ev ElectronImpact Ionization Of Ar (3p), Zehra Nur Ozer, Sadek M. Amami, Onur Varol, Murat Yavuz, Mevlut Dogan, Don H. Madison
Physics Faculty Research & Creative Works
We have measured triple differential cross sections (TDCSs) for electronimpact ionization of the 3p shell of Ar at 200 eV incident electron energy. The experiments have been performed in coplanar asymmetric energy sharing geometry. The experimental results are compared with the theoretical models of three body distorted wave (3DW) and distorted wave Born approximation (DWBA).
Revisiting Ulysses Observations Of Interstellar Helium, Brian E. Wood, HansReinhard Müller, Manfred Witte
Revisiting Ulysses Observations Of Interstellar Helium, Brian E. Wood, HansReinhard Müller, Manfred Witte
Open Dartmouth: Peerreviewed articles by Dartmouth faculty
We report the results of a comprehensive reanalysis of Ulysses observations of interstellar He atoms flowing through the solar system, the goal being to reassess the interstellar He flow vector and to search for evidence of variability in this vector. We find no evidence that the He beam seen by Ulysses changes at all from 19942007. The direction of flow changes by no more than ~03 and the speed by no more than ~0.3 km s^{–1}. A global fit to all acceptable He beam maps from 19942007 yields the following He flow parameters: V _{ISM} = 26.08 ± 0 ...
SelfOrganization Of S Adatoms On Au(111): √3r30° Rows At Low Coverage, Holly L. Walen, DaJiang Liu, Junepyo Oh, Hyunseob Lim, James W. Evans, Yousoo Kim, Patricia A. Thiel
SelfOrganization Of S Adatoms On Au(111): √3r30° Rows At Low Coverage, Holly L. Walen, DaJiang Liu, Junepyo Oh, Hyunseob Lim, James W. Evans, Yousoo Kim, Patricia A. Thiel
Chemistry Publications
Using scanning tunneling microscopy, we observe an adlayer structure that is dominated by short rows of S atoms, on unreconstructed regions of a Au(111) surface. This structure forms upon adsorption of low S coverage (less than 0.1 monolayer) on a fully reconstructed clean surface at 300 K, then cooling to 5 K for observation. The rows adopt one of three orientations that are rotated by 30◦ from the closepacked directions of the Au(111) substrate, and adjacent S atoms in the rows are separated by √ 3 times the surface lattice constant, a. Monte Carlo simulations are performed on ...
LongRange Displacive Reconstruction Of Au(110) Triggered By Low Coverage Of Sulfur, Holly L. Walen, DaJiang Liu, Junepyo Oh, Yousoo Kim, Patricia A. Thiel
LongRange Displacive Reconstruction Of Au(110) Triggered By Low Coverage Of Sulfur, Holly L. Walen, DaJiang Liu, Junepyo Oh, Yousoo Kim, Patricia A. Thiel
Chemistry Publications
We propose a new model for the c(4 × 2) phase of sulfur adsorbed on Au(110). This is a reconstruction achieved by shortrange rearrangements of Au atoms that create a pseudo4foldhollow (p4fh) site for adsorbed sulfur. The model is based partly upon the agreement between experimental STM images and those predicted from DFT, both within c(4 × 2) domains and at a boundary between two domains. It is also based on the stability of this structure in DFT, where it is not only favored over the chemisorbed phase at its ideal coverage of 0.25 ML, but also at ...
OneLoop Dominance In The Imaginary Part Of The Polarizability: Application To Blackbody And Noncontact Van Der Waals Friction, Ulrich D. Jentschura, Grzegorz Lach, Maarten Dekieviet, Krzysztof Pachucki
OneLoop Dominance In The Imaginary Part Of The Polarizability: Application To Blackbody And Noncontact Van Der Waals Friction, Ulrich D. Jentschura, Grzegorz Lach, Maarten Dekieviet, Krzysztof Pachucki
Physics Faculty Research & Creative Works
Phenomenologically important quantum dissipative processes include blackbody friction (an atom absorbs counterpropagating blueshifted photons and spontaneously emits them in all directions, losing kinetic energy) and noncontact van der Waals friction (in the vicinity of a dielectric surface, the mirror charges of the constituent particles inside the surface experience drag, slowing the atom). The theoretical predictions for these processes are modified upon a rigorous quantum electrodynamic treatment, which shows that the oneloop "correction" yields the dominant contribution to the offresonant, gaugeinvariant, imaginary part of the atom's polarizability at room temperature, for typical atomsurface interactions. The treelevel contribution to the polarizability ...
LongRange AtomWall Interactions And Mixing Terms: Metastable Hydrogen, Ulrich D. Jentschura
LongRange AtomWall Interactions And Mixing Terms: Metastable Hydrogen, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
We investigate the interaction of metastable 2S hydrogen atoms with a perfectly conducting wall, including paritybreaking SP mixing terms (with full account of retardation). The neighboring 2P_{1/2} and 2P_{3/2} levels are found to have a profound effect on the transition from the shortrange, nonrelativistic regime, to the retarded form of the CasimirPolder interaction. The corresponding P state admixtures to the metastable 2S state are calculated. We find the longrange asymptotics of the retarded CasimirPolder potentials and mixing amplitudes for general excited states, including a fully quantum electrodynamic treatment of the dipolequadrupole mixing term. The decay width ...
FineStructure Constant For Gravitational And Scalar Interactions, Ulrich D. Jentschura
FineStructure Constant For Gravitational And Scalar Interactions, Ulrich D. Jentschura
Physics Faculty Research & Creative Works
Starting from the coupling of a relativistic quantum particle to the curved Schwarzschild space time, we show that the DiracSchwarzschild problem has bound states and calculate their energies including relativistic corrections. Relativistic effects are shown to be suppressed by the gravitational finestructure constant α_{G}=Gm_{1}m_{2}/(ℏc), where G is Newton's gravitational constant, c is the speed of light, and m_{1} and m_{2} ≫ m_{1} are the masses of the two particles. The kinetic corrections due to spacetime curvature are shown to lift the familiar (n,j) degeneracy of the energy levels of the ...
Effect Of The CenterOfMass Approximation On The Scaling Of ElectronCapture Fully Differential Cross Sections, A. L. Harris, Don H. Madison
Effect Of The CenterOfMass Approximation On The Scaling Of ElectronCapture Fully Differential Cross Sections, A. L. Harris, Don H. Madison
Physics Faculty Research & Creative Works
We present results for p+He single electron capture and transfer with target excitation using the first Born approximation. The effect of approximating the center of mass of the helium atom and outgoing hydrogen atom at the respective nuclei is explored. Semianalytical results are compared for the calculations with and without the approximation, and it is shown that one must properly account for the center of mass of the atoms. It is also shown that this approximation is the result of the apparent v^{4} scaling that was previously observed with the fourbody transfer with target excitation model.
Theoretical And Experimental Investigation Of (E, 2e) Ionization Of Argon 3p In Asymmetric Kinematics At Intermediate Energy, Sadek Amami, Melike Ulu, Zehra Nur Ozer, Murat Yavuz, Suay Kazgoz, Mevlut Dogan, Oleg Zatsarinny, Klaus Bartschat, Don H. Madison
Theoretical And Experimental Investigation Of (E, 2e) Ionization Of Argon 3p In Asymmetric Kinematics At Intermediate Energy, Sadek Amami, Melike Ulu, Zehra Nur Ozer, Murat Yavuz, Suay Kazgoz, Mevlut Dogan, Oleg Zatsarinny, Klaus Bartschat, Don H. Madison
Physics Faculty Research & Creative Works
The field of electronimpact ionization of atoms, or (e, 2e), has provided significant detailed information about the physics of collisions. For ionization of hydrogen and helium, essentially exact numerical methods have been developed which can correctly predict what will happen. For larger atoms, we do not have theories of comparable accuracy. Considerable attention has been given to ionization of inert gases and, of the inert gases, argon seems to be the most difficult target for theory. There have been several studies comparing experiment and perturbative theoretical approaches over the last few decades, and generally qualitative but not quantitative agreement is ...
BornOppenheimer Study Of TwoComponent FewParticle Systems Under OneDimensional Confinement, Nirav P. Mehta
BornOppenheimer Study Of TwoComponent FewParticle Systems Under OneDimensional Confinement, Nirav P. Mehta
Physics and Astronomy Faculty Research
The energy spectrum, atomdimer scattering length, and atomtrimer scattering length for systems of three and four ultracold atoms with δfunction interactions in one dimension are presented as a function of the relative mass ratio of the interacting atoms. The BornOppenheimer approach is used to treat threebody (“HHL”) systems of one light and two heavy atoms, as well as fourbody (“HHHL”) systems of one light and three heavy atoms. Zerorange interactions of arbitrary strength are assumed between different atoms, but the heavy atoms are assumed to be noninteracting among themselves. Fermionic and bosonic heavy atoms with both positive and negative parity ...