The nuclear magnetic moment of 71As and 72As

Nuclear magnetic resonance of oriented ⁷¹As and ⁷²As nuclei has been observed in an iron host lattice at low temperatures. The resonance frequencies are v_l = 174.96(10) MHz and 282.00(11) MHz respectively for zero external field. Using B_h.f.(FeAs) = 342.9(3) kG the g-factors of the two isotopes are derived as $\text{g(}{}^{71}\text{As}\text{) = (+)0.6694(7)}\text{and}\text{g(}{}^{72}\text{As) = (?)1.0789(11)}$. Combining nuclear orientation data with these results the spin of ⁷¹As has been confirmed as $\text{I =}\text{5}\text{2}$. The magnetic moments of the $\text{5}\text{2}{}^{\mathrm{?}}$ and 2^? states in the As isotopes are discussed in the framework of the shell model with configuration mixing.     

Measurement of the nuclear magnetic moment of tritium to nine-digit accuracy

A series of ten pair spectra has been obtained by simultaneously detecting the proton and tritium NMR spectra of the gaseous TH sample, which is an analogue of molecular hydrogen. The numerical processing of the data yields the ratio F(TH)/F(HT) = 1.066 639 8933(7) of the magnetic moments of tritium and proton in the TH molecule. The relative statistical error of this result is 7 × 10⁻¹⁰. To find the nuclear magnetic moment of tritium from F(TH)/F(HT), it is sufficient to use the previously calculated correction factor δ = (1 + 20.4 × 10⁻⁹), which originates from a small asymmetry of the electron cloud of the molecule.     

Magnetic dipole moment of127Sb by NMR/ON

The technique of NMR on oriented nuclei has been applied to¹²⁷Sb to measure the magnetic dipole moment of the¹²⁷Sb ground state. Resonant destruction of gamma-ray anisotropy from¹²⁷Sb^g (I =7/2⁺) has been observed at 139.6(2) MHz forB _app=0.30(1) T andat 138.7(1) MHz forB _app=0.25(1) T. The deduced magnetic moment is ||=2.697(6) µ_N.     

磁场及磁矩的测量实验

对地磁水平分量测量实验加以改进,将其扩充为能够测量亥姆霍兹线圈磁场分布和磁针的转动惯量以及磁针磁矩的实验.使其成为一个综合性较强,适用于开展研究性实验的项目.     

Measurement of the nuclear magnetic moment of110Ag(T 1/2=24.4 s)

Nuclear magnetic resonance of¹¹⁰Ag has been observed in silver halides using the polarized neutron capture,β decay anisotropy method. The magnetic moment was determined asμ _I(¹¹⁰Ag)=2.7084 (5) nm (uncorrected).     

The nuclear magnetic moment of182Ta

The nuclear magnetic moment of¹⁸²Ta has been measured with the aid of the NMR-ON technique, using the hyperfine fieldB=–65.6±1.3T in iron. Its value =298±0.06 _N is in excellent agreement with that calculated for a Nilsson configuration, using proper parametersg _K andg _R derived from neighbouring odd-A nuclei. Agreement is also found between experimental and calculated nuclear magnetic moments of¹⁸⁴Re, which has the sameK=1/2 neutron state as¹⁸²Ta.     

First measurement of the nuclear magnetic moment of 254Es

Angular distributions of α particles and γ rays emitted by ^253,254Es, ²⁵⁵Fm, and ²⁵⁰Bk nuclei were studied using the low-temperature nuclear orientation method. Information on the hyperfine interactions of these actinide impurities in an iron host lattice is derived from experimental data and the value of magnetic moment of ²⁵⁴Es nucleus is determined.     

Pion effects on nuclear magnetic moment and transitions

The present evidence for pion contributions to magnetic moments, transitions and form factors is selectively reviewed with emphasis on the crucial evidence for specific effects. The theoretical basis will be discussed with special emphasis on the physical picture which emerges in the long wavelength limit.     

Measurement of the nuclear quadrupole moment of53Cr by laser-Rf double resonance

The hyperfine structure of the metastable atomic states (3d ⁴4s ²)⁵ D _1,2,3,4 of⁵³Cr has been measured using theABMR-LIRF method (atomic beam magnetic resonance detected by laser induced resonance fluorescence). The dipole coupling constantsA and the quadrupole coupling constantsB are found to beA(⁵ D ₁)=?17.624(2) MHzB(⁵ D ₁)=?21.847(5) MHzA(⁵ D ₂)=?25.113(2) MHzB(⁵ D ₂)=?13.485(5) MHzA(⁵ D ₃)=?35.683(2) MHzB(⁵ D ₃)=15.565(5) MHzA(⁵ D ₄)=?48.755(2) MHzB(⁵ D ₄)=63.021(5) MHz. From these measured hfs constants the electric quadrupole moment for⁵³Cr is calculated to beQ=?0.15 (5) barn. The 30% error takes into account the uncertainties due to configuration interaction effects (shielding and antishielding effects) and of deviations from pure SL-coupling for the states⁵ D _1,2,3,4.     

Magnetic hyperfine field of arsenic in nickel by NMR/ON of71,72As

The magnetic hyperfine splitting frequencies of⁷¹AsNi and⁷²AsNi in a 0.11 Tesla external magnetic field have been determined by NMR/ON method as 66.00(6) MHz and 106.17(13) MHz respectively. Using the known magnetic moments of μ(⁷¹As)=1.6735(18) and μ(⁷²As)=−2.1566(3), the hyperfine fields were deduced asB _hf(⁷¹AsNi)=12.824(19) Tesla andB _hf(⁷²AsNi)=12.807(16) Tesla.     

Observation of the nuclear magnetic octupole moment of 133Cs

We describe our high-resolution measurements of the 133Cs 6p (2)P(3/2) state hyperfine structure. An optically narrowed diode laser excites perpendicularly a highly collimated atomic beam. The spectra are calibrated with a stable reference diode laser using a rf locking scheme allowing us to determine the splittings with an accuracy of < or =2 kHz, an order of magnitude better than previous results. The magnetic dipole a, electric quadrupole b, and magnetic octupole c hyperfine coupling constants are determined. The values we obtained are a=50.288 27(23) MHz, b=-0.4934(17) MHz, and c=0.56(7) kHz. This work represents the first observation of the magnetic octupole moment of the cesium nucleus. We carry out atomic-structure calculations and determine the nuclear electric quadrupole moment Q= -3.55(4) mb and nuclear magnetic octupole moment Omega=0.82(10) b x mu(N).     

The magnetic hyperfine field of lutetium in iron by NMR/ON

Nuclear magnetic resonance of oriented¹⁷⁷Lu in iron has been found with a sample prepared by on-line implantation of¹⁷⁷Lu in iron at T<0.2 K. The broad resonance, FWHM=20.5 (1.3) MHz, has a centre frequency of _L=355.06 (51) MHz at zero external field. With the g-factor of¹⁷⁷Lu g=0.637 (3) from literature the magnetic hyperfine field of Lu in Fe is derived as B_hf=–73.12(36) T. Static nuclear orientation data are not compatible with a two site model where the nuclei which are oriented experience the hyperfine interaction found in NMR/ON. A fraction with a lower hyperfine field is necessary to explain the data.     

Ground-State hyperfine structure and nuclear magnetic moment of Thulium-169

The hyperfine structure of the 4f ¹³ 6s ^{2 2} F _7/2 ground state of Tm¹⁶⁹ has been studied with the atomic beam magnetic resonance method. By measuring strongly field-dependent transitions in external magnetic fields between 2200 and 3000 Gauss the interaction between the nuclear magnetic dipole momentμ _I and the external field was determined. These measurements yielded a direct value forμ _I independent of the electronic properties of the Tm-atom. The results are:μ _I=? 0.2310 (15)μ _n (diamagnetically corrected), magnetic dipole interaction constanta=? 374.137661(3) Mc/sec andg _J(4f ¹³ 6s ^{2 2} F _7/2)=1.141189 (3).     

The magnetic hyperfine field of bromine in iron by NMR/ON

Nuclear magnetic resonance of⁸²Br oriented at low temperature in iron has been observed with a sample prepared by ion implantation atT<0.2 K. The asymmetric resonance signal can be decomposed in a broad background signal and a narrow line of FWHM=1.8 (4) MHz which can be attributed to⁸²Br in undisturbed substitutional sites of Fe. From the center frequency of this narrow line (B _ext=0)=201.86(13) MHz we derive the magnetic hyperfine field asB _hf(BrFe)=81.38(6) T. This value is considerably larger than the result of theoretical calculations.     

Measurement of heat transfer coefficients by nuclear magnetic resonance

We demonstrate an experimental method for the measurement of heat transfer coefficient for a fluid system by magnetic resonance imaging. In this method, the temporal variation of thermally induced nuclear shielding is monitored and the average heat transfer coefficient is measured as a function of fluid velocity. We examine the cases of natural convection and forced convection at fluid velocity up to 0.8 m s(-1). These cases correspond to low dimensionless Biot (Bi) number where the heat transfer is limited by thermal convection. We demonstrate the NMR method for two simple geometries, a cylinder and a sphere, to experimentally determine the heat transfer coefficient (h) in two NMR imaging and spectroscopy systems through measuring three NMR parameters, the chemical shift, magnetization and spin self diffusion coefficient.