Search NASA⌕ Search

SEARCH · Search NASA

Results for “BOHR THEORY”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2011

The Energy Loss of Li and C Ions with MeV Energies in the Polycarbonate and Polypropylene

Stopping power and straggling of Li ions and C ions at mean energy 3.8-5.4 MeV and 5.6-6.9 MeV, respectively, in polycarbonate (PC) and at mean energy 3.7-5.2 MeV and 6.8-8.0 MeV in polypropylene (PP) foils have been measured using ion beams from a Tandetron 4130 MC accelerator. The ions scattered from a thin, primary gold target were registered by a surface barrier detector partially covered with a thin foil of the investigated polymer. The stopping power was determined from the energy difference between the signals from the ions directly backscattered from the Au layer and the ions backscattered and slowed down in the foil. The foil thickness was determined by the weighing procedure. The experimentally determined stopping powers were compared with those calculated with the SRIM 2010 code. The measured stopping powers are in good agreement for Li and C in PC, the differences being within 0.1-1.6% for Li and 0.2-2.1% for C. For Li and C in PP, the stopping powers are lower than the calculated ones, the differences being within 0.5-2.8% for Li and 3.6-6.1% for C. The energy straggling was determined from the width of the RBS signals. The experimentally determined energy straggling was found to fluctuate around the values calculated according to Bohr theory.

36 MATERIALS SCIENCE↗
NASA NTRS2015

Dynamics of the Vacuum and Casimir Analogs to the Hydrogen Atom

This paper will discuss the current viewpoint of the vacuum state and explore the idea of a "natural" vacuum as opposed to immutable, non-degradable vacuum. This concept will be explored for all primary quantum numbers to show consistency with observation at the level of Bohr theory. A comparison with the Casimir force per unit area will be made, and an explicit function for the spatial variation of the vacuum density around the atomic nucleus will be derived. This explicit function will be numerically modeled using the industry multi-physics tool, COMSOL(trademark), and the eigenfrequencies for the n = 1 to n = 7 states will be found and compared to expectation.

White, Harold↗
DOE OSTI2015

Gravitational Bohr’s model with Newton’s and Weber’s potentials

Similarity between Newtonian gravitational force and Coulomb’s force leads one to define gravitational electric and magnetic fields or gravito-electromagnetic fields. Also, one may define a gravitational Bohr’s theory in analogy with the electromagnetic Bohr’s theory for which the latter is quite successful in explaining some properties of hydrogen atom. Unlike to the Coulomb’s force, the Newton‘s force is believed to be an approximated theory of gravity as it is unable to explain the Mercury’s orbit. This paper discusses the gravitational Bohr’s theory by taking into account the Newton’s potential and Weber’s potential; the later is a modified Newton’s gravitational potential that conforms, to some degrees, to the anomaly of the Mercury’s orbit.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

How to understand the tunneling in attosecond experiment?: Bohr–Einstein photon box Gedanken experiment, tunneling time and the wave particle duality

The measurement of the tunneling time (T-time) in today’s attosecond and strong field (low-frequency) experiments, despite its controversial discussion, offers a fruitful opportunity to understand time measurement and the time in quantum mechanics. In addition, as we will see in this work, a related controversial issue is the particulate nature of the radiation. The T-time in attosecond experiment and its different aspects and models, is discussed in this work, especially in relation to my model of real T-time (Kullie, 2015), where a good agreement with the experiment and an intriguing similarity to the Bohr–Einstein photon box Gedanken experiment was found. The tunneling process itself is still not well understood, but I am arguing that a scattering mechanism (by the laser wave packet) offers a possibility to understand the tunneling process in the tunneling region. This is related to the question about the corpuscular nature of light which is widely discussed in modern quantum optics experiments.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2013

Bohr-Sommerfeld quantization condition for Dirac states derived from an Ermakov-type invariant

It is shown that solutions of the second-order decoupled radial Dirac equations satisfy Ermakov-type invariants. These invariants lead to amplitude-phase-type representations of the radial spinor solutions, with exact relations between their amplitudes and phases. Implications leading to a Bohr-Sommerfeld quantization condition for bound states, and a few particular atomic/ionic and nuclear/hadronic bound-state situations are discussed.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Bohr-like black holes

The idea that black holes (BHs) result in highly excited states representing both the “hydrogen atom” and the “quasi-thermal emission” in quantum gravity is today an intuitive but general conviction. In this paper it will be shown that such an intuitive picture is more than a picture. In fact, we will discuss a model of quantum BH somewhat similar to the historical semi-classical model of the structure of a hydrogen atom introduced by Bohr in 1913. The model is completely consistent with existing results in the literature, starting from the celebrated result of Bekenstein on the area quantization.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

Collective motion of two-electron atom in hyperspherical adiabatic approximation

This work is devoted to calculate bound states in the two-electron atoms. The separation of variables has carried out in hyper spherical coordinate system (R, θ, α). Assuming collective motion of the electrons, where the hper angle (α∼π/4) and (θ∼π). The separation of the rotational variables leads to system of differential equations with more simple form as compared with non restricted motion. Energy of doubly excited P{sup e} and D{sup 0} states are calculated semi classically by using quantization condition of Bohr -Somerfield. The results compared with previously published data.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2014

Bohr’s molecular model, a century later

The Bohr model, newly reconciled with quantum mechanics in the limit of infinite dimensions and modestly extended, yields surprisingly accurate predictions for hydrogen and other small molecules.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2015

On the belated discovery of fission

A remarkable sequence of missteps, misfortune, and oversights delayed the discovery of nuclear fission until the eve of World War II—and likely altered history’s course.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2016

Quantum probabilities from quantum entanglement: experimentally unpacking the Born rule

The Born rule, a foundational axiom used to deduce probabilities of events from wavefunctions, is indispensable in the everyday practice of quantum physics. It is also key in the quest to reconcile the ostensibly inconsistent laws of the quantum and classical realms, as it confers physical significance to reduced density matrices, the essential tools of decoherence theory. Following Bohr's Copenhagen interpretation, textbooks postulate the Born rule outright. But, recent attempts to derive it from other quantum principles have been successful, holding promise for simplifying and clarifying the quantum foundational bedrock. Moreover, a major family of derivations is based on envariance, a recently discovered symmetry of entangled quantum states. Here, we identify and experimentally test three premises central to these envariance-based derivations, thus demonstrating, in the microworld, the symmetries from which the Born rule is derived. Furthermore, we demonstrate envariance in a purely local quantum system, showing its independence from relativistic causality.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2023

Schematic model for induced fission in a configuration-interaction approach

We model fission at barrier-top energies in a simplified model space that permits comparison of different components of the residual nucleon-nucleon interaction. The model space is built on particle-hole excitations of reference configurations. These are Slater determinants of uniformly spaced orbitals characterized only by their quantum numbers and orbital energies. The residual interaction in the Hamiltonian includes the diabatic interaction connecting similar orbitals at different deformations, the pairing interaction between like nucleons, and a schematic off-diagonal neutron-proton interaction. We find that the fission reaction probability is sensitive to the off-diagonal neutron-proton interaction much more than to the pairing and the diabatic interactions. In particular, the transmission coefficients become insensitive to the strength of the pairing interaction when the neutron-proton interaction is large. Here, we also find that the branching ratio is insensitive to the final-state scission dynamics, as is assumed in the well-known Bohr-Wheeler theory.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS2000

Some Thermodynamic Considerations on the Physical and Quantum Nature of Space and Time

It is suggested that the Planck h = m(sub k)c Lambda(sub k) and the Boltzmann k = m(sub k)c nu(sub k)Constants have stochastic foundation. It is further suggested that a body of fluid at equilibrium is composed of a spectrum of molecular clusters (energy levels) the size of which are governed by the Maxwell-Boltzmann distribution function. Brownian motions are attributed to equilibrium between suspensions and molecular clusters. Atomic (molecular) transition between different size atomic- (molecular-) clusters (energy levels) is shown to result in emission/absorption of energy in accordance with Bohr's theory of atomic spectra. Physical space is identified as a tachyonic fluid that is Dirac's stochastic ether or de Broglie's hidden thermostat. Compressibility of physical space, in accordance with Planck's compressible ether, is shown to result in the Lorentz-Fitzgerald contraction, thus providing a causal explanation of relativistic effect in accordance with the perceptions of Poincare and Lorentz. The invariant Schrodinger equation is derived from the invariant Bernoulli equation for incompressible potential flow. Following Heisenberg a temporal uncertainty relation is introduced as Delta(nu(sub Beta)) Delta(Rho(sub Beta)) > = k.

Sohrab, Siavash H.↗
DOE OSTI2010

Quantum Integers

In number theory, a partition of a positive integer n is a way of writing n as a sum of positive integers. The number of partitions of n is given by the partition function p(n). Inspired by quantum information processing, we extend the concept of partitions in number theory as follows: for an integer n, we treat each partition as a basis state of a quantum system representing that number n, so that the Hilbert-space that corresponds to that integer n is of dimension p(n); the 'classical integer' n can thus be generalized into a (pure) quantum state ||psi(n) > which is a superposition of the partitions of n, in the same way that a quantum bit (qubit) is a generalization of a classical bit. More generally, rho(n) is a density matrix in that same Hilbert-space (a probability distribution over pure states). Inspired by the notion of quantum numbers in quantum theory (such as in Bohr's model of the atom), we then try to go beyond the partitions, by defining (via recursion) the notion of 'sub-partitions' in number theory. Combining the two notions mentioned above, sub-partitions and quantum integers, we finally provide an alternative definition of the quantum integers [the pure-state |psi'(n)> and the mixed-state rho'(n),] this time using the sub-partitions as the basis states instead of the partitions, for describing the quantum number that corresponds to the integer n.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗