EFFECTS OF NONCOMMUTATIVITY ON LIGHT HYDROGEN-LIKE ATOMS AND PROTON RADIUS

We study the corrections induced by the theory of noncommutativity, in both space–space and space–time versions, on the spectrum of hydrogen-like atoms. For this, we use the relativistic theory of two-particle systems to take into account the effects of the reduced mass, and we use perturbation methods to study the effects of noncommutativity. We apply our study to the muon hydrogen with the aim to solve the puzzle of proton radius [R. Pohl et al., Nature466, 213 (2010) and A. Antognini et al., Science339, 417 (2013)]. The shifts in the spectrum are found more noticeable in muon H(μH) than in electron H(eH) because the corrections depend on the mass to the third power. This explains the discrepancy between μH and eH results. In space–space noncommutativity, the parameter required to resolve the puzzle θ ss ≈(0.35 GeV )-2, exceeds the limit obtained for this parameter from various studies on eH Lamb shift. For space–time noncommutativity, the value θ st ≈(14.3 GeV )-2 has been obtained and it is in agreement with the limit determined by Lamb shift spectroscopy in eH. We have also found that this value fills the gap between theory and experiment in the case of μD and improves the agreement between theoretical and experimental values in the case of hydrogen–deuterium isotope shift.

NUCLEUS POLARIZABILITY CONTRIBUTION TO THE HYDROGEN–DEUTERIUM ISOTOPE SHIFT

The correction to the hydrogen–deuterium isotope shift due to the proton and deuteron polarizability is evaluated on the basis of modern experimental data on the structure functions of inelastic lepton–nucleus scattering. The numerical value of this contribution is equal to 63 ± 12 Hz.

The Carbon-13 Magnetic Resonance Spectrum of Propane

The carbon-13 magnetic resonance spectra of propane and of propane-2,2-d2 are analyzed to give 1j(13C1,H) = 124.35, 1J(13C2,H) = 125.35, 2J(13C1,H) = −4.25, 2J(13C2,H) = −4.39, 3J(13C,H) = 5.80, 3J(H,H) = 7.375, 4j(H,H) < ± 0.18 Hz. The deuterium isotope shift at C2 is 0.72 ± 0.10 p.p.m. to high field.

Carbon-13 Nuclear Magnetic Resonance Spectra of Carcinogenic Polynuclear Hydrocarbons. I. 3-Methylcholanthrene and Related Benzanthracenes

Carbon-13 chemical shifts are reported for a series of carcinogenically active and related inactive polynuclear hydrocarbons. Resonance assignments for complex systems such as 3-methylcholanthrene, dibenzanthracenes, benz[a]anthracene and its 7-methyl and 7,12-dimethyl derivative, have been made primarily from a study of simpler models, including phenanthrene, triphenylene, and anthracene. Selective proton decoupling has been employed extensively. Quaternary carbon assignments have been aided by deuterium isotope shift and spin–lattice relaxation time measurements. Vicinal C—D couplings have been found to be unreliable as means of assignment for quaternary carbons.