Measurement of the magnetic moment of the 7+ isomer in 198Tl

Using the atomic beam magnetic resonance method the hyperfine structure separation of $\text{1.9}\text{h}{}^{\mathrm{198m}}\text{Tl}\text{(I}{}^{\mathrm{\pi }}\text{= 7}{}^{\mathrm{+}}\text{)}$ has been measured in the ${}^2\text{P}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ atomic ground state. From the hyperfine structure splitting the nuclear magnetic dipole moment has been deduced. The results are: Δν = 4500 (68) MHz, μ_I = 0.641(10)μ_N. This is an improvement of approximately one order of magnitude compared to a previous measurement. The quoted value of the magnetic dipole moment includes corrections for the hyperfine structure anomaly and for diamagnetic shielding.     

Magnetic moment of the 72+[404] ground state of 10.5 h 175Ta

The magnetic hyperfine splitting ν_M = |gμ_NB_HF/h| of ${}^{175}\text{Ta}\text{(J}{}^{\mathrm{\pi }}\text{=}\text{7}\text{2}{}^{\mathrm{+}}$; $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 10.5}\text{h}\text{)}$ in Fe has been measured with the technique of nuclear magnetic resonance on oriented nuclei as 320.4(1) MHz. With the known hyperfine field $\text{B}{}_{\mathrm{<mtext>HF</mtext>}}\text{(}\text{Ta}\text{Fe}\text{) = ?648(13)}\text{kG}$ the magnetic moment of the $\text{7}\text{2}{}^{\mathrm{+}}\text{[404]}$ ground state of ¹⁷⁵Ta is deduced to be $\text{¦μ¦ = 2.27(5)μ}{}_{\mathrm{<mtext>N</mtext>}}$.     

Hyperfine structure of the 53P1 state of 115Cdm

The magnetic fields at which Zeeman sublevels cross in the excited 5³P₁ state of the 43-day isomer ¹¹⁵Cd^m have been determined for three pairs of levels. The crossing fields are used to determine the magnetic dipole hyperfine structure constant $\text{A(}{}^3\text{P}{}_1\text{) = ?656.491 (4)}\text{MHz}$ and the quadrupole constant $\text{B(}{}^3\text{P}{}_1\text{) = 129.39 (6)}\text{MHz}$.     

Hyperfine structure determination of the 72D52state of 133Cs

The magnitude and sign of the hyperfine structure of $\text{7}{}^2\text{D}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}$state of ¹³³Cs have been measured. We find the magnetic dipole coupling constant to be A = -1.7 (2) MHz.     

Microwave spectrum of the IO radical

The two lowest rotational transitions of the IO radical in the ${}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ ground electronic state have been observed by means of a Stark modulated spectrometer. The effective rotational constants in the ${}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ state, the centrifugal distortion constant, the axial component of the magnetic hyperfine interaction, and the nuclear electric quadrupole coupling constant are determined accurately. It was necessary to take into account the second-order effects from the matrix elements off-diagonal in J for the analysis of the hyperfine structure. An equilibrium internuclear distance r_e is calculated to be 1.8677 ± 0.0028 Å from the effective rotational constant $\text{B}{}_0\text{(}{}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}\text{)}$, combined with α₃ from the A²Π → X²Π transition.     

Nuclear magnetic moment of the 9.7 h 12− isomer 196mAu

The magnetic hyperfine splitting v_M=|gμ_NB_HF/h| of ^196mAu (j^π=12^?; configuration ¦(π$\text{11}\text{2}$($\text{v}\text{13}\text{2}{}^{\mathrm{+}}\text{)〉}{}_{12}{}^{\mathrm{?}}$; $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 9.7}\text{h}\text{)}$ as dilute impurity in Ni has been determined with nuclear magnetic resonance on oriented nuclei as 96.0(2) MHz. With the known hyperfine field B_HF = ?264.4(3.9) kG corrected for hyperfine anomalies the g-factor and magnetic moment of ^196mAu are deduced to be |g| = 0.476(7) and |μ| = 5.72(8) μ_N. Taking into account the known magnetic properties of $\text{π}\text{1}\text{2}{}^{\mathrm{?}}$ and $\text{v}\text{13}\text{2}{}^{\mathrm{+}}$ isomeric states in the neighbouring odd Pt, Au and Hg nuclei the structure of the 12^? state is discussed.     

Microwave spectrum of the SF radical

The lowest rotational transition of the SF radical in the ${}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ state has been observed and analyzed to determine the effective rotational constant B_eff and a magnetic hyperfine constant h to be 16 553.76₀ ± 0.052 MHz and 428.6₀ ± 0.71 MHz, respectively. The dipole moment was calculated from the Stark effects to be 0.79₄ ± 0.012 D.     

Stroboscopic observation of quadrupole hyperfine interactions

A stroboscopic technique for the observation of quadrupole hyperfine interactions of isomeric nuclear states has been successfully developed. The inherent precision and resolution of this technique have been demonstrated by measuring the quadrupole hyperfine frequency for ${}^{69}\text{Ge(}\text{9}\text{2}{}^{\mathrm{+}}{}_1\text{, τ = 4.0μ)}$ in Zn metal at several temperatures; ω₀ = [19.67 ± 0.06] × 10⁶s^?1 (at 623 ± 3 K).     

Measurement of the electric quadrupole moment of the 482 keV state of 181Ta by the time differential perturbed angular correlation technique

The electric quadrupole interaction of the 482 keV state of ¹⁸¹Ta in an environment of metallic rhenium has been investigated by time differential angular correlation measurements. For the field gradient calibration a recent observation^{1, 2}) of the quadrupole splitting of the 6.3 keV line of ¹⁸¹Tain the same environment has been used. Adopting the quadrupole moment of the ground state which was derived from muonic X-ray data ³) we obtain $\text{Q}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{(482}\text{keV}\text{) = 2.51 ± 0.15}\text{b}$. A comparison of the intrinsic quadrupole moment Q₀ with that of the ground state revealed that the excited state is slightly less deformed: $\text{Q}{}_0\text{(}\text{5}\text{2}{}^{\mathrm{+}}\text{)/Q}{}_0\text{(}\text{7}\text{2}{}^{\mathrm{+}}\text{) = 0.936 ± 0.014}$. A measurement of the temperature dependence between liquid nitrogen and room temperature showed that the electric quadrupole interaction remains essentially constant.     

Isomeric E1 and M1 transitions in 177Ta and in neighbouring odd-A Lu and Ta isotopes

Delayed γ-ray spectra as well as time distributions have been measured applying the r.f.-γ method and the method of delayed γ-γ coincidences. Using the reaction ¹⁷⁵Lu(α, 2n)¹⁷⁷Ta, the half-lives of the levels at 70.6 and 73.6 keV in ¹⁷⁷Ta have been determined as $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 80±10}\text{ns}$ and $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 370±50}\text{ns}$, respectively. In further experiments, upper limits for the lifetimes of the $\text{9}\text{2}{}^{\mathrm{?}}\text{[514]}$ and $\text{5}\text{2}{}^{\mathrm{+}}\text{[402]}$ states in ¹⁷¹Lu and ¹⁷³Lu were estimated. Comparisons of the experimental half-lives to Weisskopf and Nilsson model predictions are performed taking into account pairing correlations. For the calculations, a modified Nilsson Hamiltonian has been used. The hindrance factors obtained are summarized together with those deduced for corresponding transitions in neighbouring odd-proton nuclei. From the experimental results in ¹⁷⁷Ta, conclusions have been drawn on the possible value of the constant k₂ occurring in the magnetic dipole operator.     

Measurement of the nuclear magnetic dipole moments of 177Hf and 179Hf with the atomic beam magnetic resonance method

The nuclear ground-state magnetic dipole moments of ¹⁷⁷Hf and ¹⁷⁹Hf have been determined with the atomic beam magnetic resonance method. The results are: $\text{μ}{}_{\mathrm{<mtext>I</mtext>}}\text{(}{}^{177}\text{Hf}\text{= 0.7836(6)μ}{}_{\mathrm{<mtext>N</mtext>}}\text{, μ}{}_{\mathrm{<mtext>I</mtext>}}\text{(}{}^{179}\text{Hf) = ?0.6329(13) μ}{}_{\mathrm{<mtext>N</mtext>}}$ (uncorrected for diamagnetic shielding).     

The dipole moment of the FO radical

The electric dipole moment of the FO radical (${}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$) has been directly measured by observing its saturated absorption laser magnetic resonance spectrum (v = 1 ← 0) in the presence of a moderate electric field. The resulting dipole moment [μ(v = 0) = 0.0043(4) D, μ(v = 1) = 0.0267(9) D] is extremely small, and shows a large relative change with vibrational state. The sign of the dipole moment is the same for the two vibrational states. Previous failures to detect microwave or gas phase EPR spectra of FO are fully explained by this small dipole moment.     

Laser magnetic resonance spectrum of BrO (2Π12 ← 2Π32)

Magnetic dipole transitions between the ${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ and ${}^2\text{Π}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ components of the ground electronic state of BrO have been detected using the technique of laser magnetic resonance on three CO₂ laser lines between 964 and 970 cm^?1. This is the first direct observation of the ${}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ state in BrO. The spin-orbit splitting parameter, A, is determined to be ?967.9831(2) cm^?1 for ⁷⁹Br¹⁶O and ?967.9981(2) cm^?1 for ⁸¹Br¹⁶O. Accurate values for the rotational constant $\text{B}{}^{\mathrm{<mtext>eff</mtext>}}\text{(}{}^2\text{Π}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)}$, the hyperfine parameters ($\text{b}{}_{\mathrm{F}}\text{+}\text{2c}\text{3}$) and d, the Λ-doubling parameter p, and the Zeeman parameter g| are also determined from an analysis of the measured spectra.     

Lifetimes and g-factors of the 6− and 7− isomers in 66Ga and 68Ga

The 6^? and 7^? isomeric states in ⁶⁶Ga and ⁶⁸Ga at 1440.9 and 1229.6 keV, respectively, have been populated with the (¹³C, 2np) and (¹⁵N, n2p) reactions on natural Fe. The half-lives of these states have been measured to be $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(6}{}^{\mathrm{?}}\text{,}{}^{66}\text{Ga}\text{) = 57.3 ± 1.2}\text{ns}$ and $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{(7}{}^{\mathrm{?}}\text{,}{}^{68}\text{Ga}\text{) = 64 ± 2}\text{ns}$. Using previous data on the hyperfine field of Ga in Fe, the g-factors of these states have been determined by means of the TDPAD method. The results are $\text{g(6}{}^{\mathrm{?}}\text{,}{}^{66}\text{Ga}\text{) = 0.129 ± 0.003}$ and $\text{g(7}{}^{\mathrm{?}}\text{,}{}^{68}\text{Ga}\text{) = 0.105 ± 0.003}$. These values are in very good agreement with the independent particle model if one assumes the and configurations and uses the empirical proton and neutron g-factors from odd-A neighboring nuclei instead of the Schmidt values. The large disagreements with experiment when Schmidt values are used show that core polarization effects are important in these nuclei.     

Determination of the spectroscopic quadrupole moments of 131Cs, 132Cs and 136Cs

Nuclear spectroscopic quadrupole moments of the radioactive isotopes ¹³¹Cs, ¹³²Cs, and ¹³⁶Cs have been determined from the hyperfine structure of the $\text{6}{}^2\text{P}{}_{\mathrm{<mtext>3</mtext><mtext>2</mtext>}}$ state by the level crossing method. The results including a Sternheimer correction are: $\text{Q}{}_{\mathrm{<mtext>s</mtext>}}\text{(}{}^{131}\text{Cs}\text{) = ?0.625(6)}\text{b}$, $\text{Q}{}_{\mathrm{<mtext>s</mtext>}}\text{(}{}^{132}\text{Cs}\text{) = +0.508(7)}\text{b}$, $\text{Q}{}_{\mathrm{<mtext>s</mtext>}}\text{(}{}^{136}\text{Cs}\text{) = +0.225(10)}\text{b}$. The quadrupole moments of all the Cs isotopes from A = 131 to A = 137 are recalculated. It is shown, that nuclear quadrupole moments of a specific isotope obtained from different atomic P-states only agree within the limits of error after application of the Sternheimer correction. The increase of Q_s with decreasing neutron number conforms with other observations and theoretical calculations stating that for elements around Z = 55 nuclear deformation develops below N = 82. The staggering of the sign of Q_s may be interpreted as consequence of an oblate-prolate degeneracy of the nuclear energy surface. Some magnetic moments have been slightly improved: $\text{μ}{}_{\mathrm{<mtext>I</mtext>}}\text{(}{}^{132}\text{Cs}\text{) = 2.219(7) μ}{}_{\mathrm{<mtext>N</mtext>}}$, $\text{μ}{}_{\mathrm{<mtext>I</mtext>}}\text{(}{}^{136}\text{Cs}\text{) = 3.705(15)μ}{}_{\mathrm{<mtext>N</mtext>}}$ (corrected for diamagnetism).     

The nuclear quadrupole interaction in Pr3+:LaF3 — An optical-RF double resonance measurement of the ground electronic state

The nuclear quadrupole hyperfine splittings of Pr³⁺ in LaF₃ have been measured for the ground electronic state using a RF optical resonance technique. A hamiltonian $\text{H}\text{= P[(I}{}^2{}_{\mathrm{z}}\text{?}\text{1}\text{3}\text{I(I+1) + (η/6)(I}{}^2{}_{\mathrm{+}}\text{?I}$²_-)] was fitted to the data with zP=4.185 ± 0.003 MHzandη = 0.105 ± 0.010. Linewidths of 180 kHz were observed.     

Nuclear magnetic moment of the 3.9 s112− isomer 193mAu

The magnetic hyperfine splitting ν_M = |gμ_NB_HF/h| of ${}^{\mathrm{<mtext>193</mtext><mtext>m</mtext>}}\text{Au}\text{(j}{}^{\mathrm{\pi }}\text{=}\text{11}\text{2}{}^{\mathrm{?}}\text{, E = 290}\text{keV}$; $\text{T}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{= 3.9}\text{s}\text{)}$ as a dilute impurity in Ni has been measured with nuclear magnetic resonance on oriented nuclei as 226.4(2) MHz. With the known hyperfine field B_HF = ?264.4(3.9) kG corrected for hyperfine anomalies the g-factor and magnetic moment of ^193mAu are deduced to be |g| = 1.123(17) and |μ| = 6.18(9) μ_N.     

The determination of the electric dipole moment of H2CS in the Ã1A2 excited state using dye-laser electric field spectroscopy

An electric field spectrum of thioformaldehyde has been measured for the 4₀¹ vibronic band of the $\text{A}\text{?}{}^1\text{A}{}_2\text{-}\text{X}\text{?}{}^1\text{A}{}_1$ electronic transition, using a tunable dye laser as the radiation source. Measurements of the Stark splittings of a number of lines in electric fields up to 8.7 kV/cm lead to a value of 0.79 ± 0.04 D for the excited state dipole moment. The decrease of dipole moment on excitation is compared with the equivalent change in formaldehyde and with predictions from ab initio calculations.