Year-2017 nuclear quadrupole moments

A ‘year-2017’ set of nuclear quadrupole moments, Q, is presented. Compared to the previous, ‘year-2008’ set, a major revision of the value, or an improvement of the accuracy is reported for ²₁H, ^{37, 39}₁₈Ar, ^{39, 40, 41}₁₉K, ⁶⁷₃₀Zn, ₄₈Cd, ₄₉In, ₅₀Sn (Mössbauer state), ₅₁Sb, ₈₇Fr and ₉₀Th. Slight improvements or valuable reconfirmations exist for ₄Be, ₆C, ₁₆S, ₁₇Cl, ₃₃As, ₃₅Br, ₅₃I, ₅₄Xe, ₅₆Ba, ₅₇La and ₇₂Hf.     

The argon nuclear quadrupole moments

New standard values -116(2) mb and 76(3) mb are suggested for the nuclear quadrupole moments (Q) of the ³⁹Ar and ³⁷Ar nuclei, respectively. The Q values were obtained by combining optical measurements of the quadrupole coupling constant (B or eqQ/h) of the 3s²3p⁵4s[3/2]₂ (³P^o) and 3s²3p⁵4p[5/2]₃ (³D^e) states of argon with large scale numerical complete active space self-consistent field and restricted active space self-consistent field calculations of the electric field gradient at the nucleus (q) using the LUCAS code, which is a finite-element based multiconfiguration Hartree–Fock program for atomic structure calculations.     

Quantum phase for an electric quadrupole moment in noncommutative quantum mechanics

We study the noncoInmutative nonrelativistic quantum dynamics of a neutral particle, which possesses an electric qaudrupole moment, in the presence of an external magnetic field. First, by intro ducing a shift for the magnetic field, we give the Schrodinger equations in the presence of an external magnetic field both on a noncommutative space and a noncomlnutative phase space, respectively. Then by solving the SchrSdinger equations both on a noneommutative space and a noncommutative phase space, we obtain quantum phases of the electric quadrupole moment, respectively. Wc demonstrate that these phases are geometric and dispersive.     

Relation between electric quadrupole and magnetic dipole nuclear moments

The values of electric quadrupole moments are described by gyromagnetic ratios of bound and free nucleons. A comparison with the experimental data shows an agreement within 15% for non-magic strongly deformed nuclei and within 50% for other ones. The expressions obtained are sensitive to a change in the order of subshell filling which takes place for proton and neutron subshells near Fermi surface.     

g factors of nuclear low-lying states:A covariant description

The g factors and spectroscopic quadrupole moments of low-lying excited states 2+1,…,81+ in 24Mg are studied in a covariant density functional theory.The wave functions are constructed by configuration mixing of axially deformed mean-field states projected on good angular momentum.The mean-field states are obtained from the constraint relativistic point-coupling model plus BCS calculations using the PC-F1 parametrization for the particle-hole channel and a density-independent delta-force for the particle-pa...     

Full relativistic calculations of the quadrupole and electric field gradients for C2, N2, and O2

In the present work we calculate the energies,quadrupole moments,and electric field gradients(EFGs) of molecules C2,N2,and O2 based on the DIRRCI method with basis aug-cc-pVTZ-DK.We prove that the quadratic force constant k2 is the product of charge and EFG at its equilibrium nuclear distance.The dipole charge distributions for these symmetrical molecules are all in equilibrium,however,the quadrupole charge distributions are far from equilibrium;among these,there is the most remarkable deviation from equilibrium for N2,for its many charges concentrate on two sides of the molecule,which is in agreement with the well-known characteristic of the nitrogen molecule.The relativistic effect is remarkable even for the same period.     

Line shape analysis in nuclear quadrupole resonance spectroscopy (I=3/2)

Following the treatment of Vega (1973), the theoretical expressions for the second moments in nuclear quadrupole resonance (nqr) due to dipole-dipole interactions have been derived for the system containing the nuclei with spinI=3/2. Cases with the orientation of the static magnetic field and the interactions with the other magnetic nuclei are also dealt with.     

磁偶极和电四极在磁各向异性介质中的辐射功率

在经典电动力学的框架下,研究了磁各向异性介质中的电磁辐射问题,得到了磁偶极和电四极在磁各向异性介质中的辐射功率表达式.进一步地,通过把各向同性介质中的μrii代入所得辐射功率表达式,得到了与文献相符合的结果,验证了所得结果的正确性.研究结果表明磁偶极和电四极在磁各向异性介质中的辐射功率大小与磁各向异性介质的μrii大小有关,对判断磁偶极和电四极在磁各向异性介质中的辐射效果有较大的帮助.     

电四极矩对高次谐波产生的贡献

通过数值求解强场近似下单电子原子的含时薛定谔方程,研究了在强线偏振激光场下,氢原子电四极矩对高次谐波产生的贡献.研究结果表明,在强激光场的作用下,在偶极矩的影响下氢原子能够产生奇次谐波,当激光场强度增加到一定值时,氢原子在电四极矩的作用下产生了偶次谐波.根据谐波功率谱和时频分析图并结合半经典三步模型分析了偶次高次谐波产生机制,并对产生的物理现象做出了合理的解释.     

Calculations of molecular multipole electric moments of a series of exo-insaturated four-membered heterocycles,Y = CCH2CH2X

The influence of ring puckering angle on the multipole moments of sixteen four-membered heterocycles (1-16) was theoretically estimated using MP2 and different DFTs in combination with the 6-31+G(d,p) basis set. To obtain an accurate evaluation, CCSD/cc-pVDZ level and, the MP2 and PBE1PBE methods in combination with the aug-cc-pVDZ and aug-cc-pVTZ basis sets were performed on the planar geometries of 1-16. In general, the DFT and MP2 approaches provided an identical dependence of the electrical properties with the puckering angle for 1-16. Quantitatively, the quality of the level of theory and basis sets affects significant the predictions of the multipole moments, in particular for the heterocycles containing C=O and C=S bonds. Convergence basis sets within the MP2 and PBE1PBE approximations are reached in the dipole moment calculations when the aug-cc-pVTZ basis set is used, while the quadrupole and octupole moment computations require a larger basis set than aug-cc-pVTZ. On the other hand, the multipole moments showed a strong dependence with the molecular geometry and the nature of the carbon-heteroatom bonds. Specifically, the C-X bond determines the behavior of the μ(?), θ(?) and ?(?) functions, while the C=Y bond plays an important role in the magnitude of the studied properties.     

Electric Field Gradients of Fluorides Calculated by the Full Potential KKR Green's Function Method

We report on the calculation of electric field gradients (EFGs) of MgF₂, MnF₂, CoF₂, NiF₂ and ZnF₂. EFGs were calculated by the full potential Korringa–Kohn–Rostoker (KKR) Green's function method in the framework of the density functional theory. While EFG calculation of these fluorides are rather difficult in the muffin-tin-potential model, due to its sensitivity to the muffin-tin radius, no difficulties arise in the present full potential treatments. EFGs calculated by this method well reproduce experimental data.     

Bound states for a Coulomb-type potential induced by the interaction between a moving electric quadrupole moment and a magnetic field

We discuss the arising of bound states solutions of the Schrödinger equation due to the presence of a Coulomb-type potential induced by the interaction between a moving electric quadrupole moment and a magnetic field. Furthermore, we study the influence of the Coulomb-type potential on the harmonic oscillator by showing a quantum effect characterized by the dependence of the angular frequency on the quantum numbers of the system, whose meaning is that not all values of the angular frequency are allowed.     

Current electric quadrupole moments of atoms and nuclei

It is shown that current electric multipoles exist. Their field is electrostatic and it is unrelated to the existence of a net electric charge. At long range, it is the same as the field of the corresponding charge electric multipoles. Current electric multipoles arise during the motion of magnetic multipoles. An orbital motion of magnetic dipoles, a precession of a current-carrying loop, and the motion of magnetic quadrupoles all lead to current electric quadrupole moments. Expressions for the current electric quadrupole moments of atoms and nuclei are derived.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 53–58, July, 1991.The author wishes to thank S. A. Kuten' and V. I. Rapoport for useful comments offered during the writing of this paper and for a discussion of the results.     

Static electric quadrupole and hexadecapole moments of nuclei

Ground-state static electric quadrupole and hexadecapole moments of even nuclei are calculated microscopically. Rare-earth, actinide and neutron-deficient nuclei with 50 <Z, N < 82 and neutron-rich nuclei with 28 < Z < 50, 50 < N < 82 are studied. Fairly good agreement with experiment is found. In the actinide region, the electric moments of fission isomers are also examined.     

Ratio of the electric quadrupole moments of122,124Sb

Low temperature nuclear orientation experiments have been performed with^122,124Sb in Sb and Zn single crystals. The ratio of the quadrupole moments of¹²⁴Sb and¹²²Sb is derived from the data asQ ¹²⁴/Q ¹²²= +2.17 (11). The sign of the effective electric field gradient at the nuclear site of Sb was found to be negative for host Sb and positive for host Zn.     

Emission of nuclear quadrupole resonance from polycrystalline hexamethylenetetramine

The angular dependence of the nuclear quadrupole resonance (NQR) signal intensity emitted from polycrystalline hexamethylenetetramine has been analytically investigated for all directions for non-contact detection of chemicals by nuclear quadrupole resonance. The field pattern of the NQR signal from a column sample was measured. The emitted patterns were the same as that from a united single magnetic dipole, which fitted well to the estimation based on quadrupole principle axis system. This result is helpful to design an antenna for NQR remote detection.     

Precision measurements of nuclear quadrupole moments by muonic X-rays

The electric multipole hyperfine interaction in muonic atoms is discussed. In particular, the influence of the finite size of the nuclear electric multipole-charge distribution on the values of nuclear spectroscopic multipole moments that are extracted from muonic hyperfine measurements is considered. It is shown that nuclear electric quadrupole moments can be deduced from the observed hyperfine splittings of muonic M X-ray transitions with high precision and practically independently of the model nuclear quadrupole-charge density. Measurements of the ground-state electric quadrupole moments of 11 deformed nuclei in and near the rare-earth region are discussed.     

Systematic study of rotational energy formulae for superdeformed bands in La and Ce isotopes

The experimental rotational spectra of superdeformed(SD) bands of ~(130)La, ~(131)Ce(1,2), ~(132)Ce(1,2,3) and133 Ce(1,2,3) in the A～130 mass region are systematically analyzed with the four parameter formula, power index formula, nuclear softness formula, and VMI model. It is observed that out of all the formulae, the four parameter formula suits best for the study of the ~(130)La, ~(131)Ce(1,2), ~(132)Ce(2,3) and ~(133)Ce(1,2,3) SD bands. The four parameter formula works efficiently in determining the band head spin of the ~(130)La, ~(131)Ce(1,2) ~(132)Ce(2,3) and ~(133)Ce(1,2,3) SD bands. Good agreement is seen between the calculated and observed transition energies whenever the accurate spin is assigned. In ~(132)Ce(1), the power index formula is found to work better than the other three formulae. The dynamic moment of inertia is also calculated for all the formulae and its variation with the rotational frequency is investigated.