Subpicosecond photon echoes by using nanosecond laser pulses

Subpicosecond time resolutions have been obtained in photon echoes when a sample was excited by two nanosecond dye laser pulses with a smooth and broad spectrum. The dye laser was pumped by second harmonics of a Q-switched Nd:YAG laser, and the pulse width was 10 ns. The sample was 3% Nd³⁺-doped silicate glass, and the center frequency of the dye laser was tuned at 5910 Å on resonance with the ⁴I_{$\text{9}\text{2}$} ? ²G_{$\text{7}\text{2}$}, ⁴G_{$\text{5}\text{2}$} transition of Nd³⁺. The homogeneous transverse relaxation time T₂ was measured to be 91 ps at 10 K in agreement with the previous measurements by picosecond pulses.     

Energies of the n2S12 and n2D32,52 states of Cs

Using the technique of Doppler-free two-photon spectroscopy the energies of the n²S_{$\text{1}\text{2}$} (12 ? n ? 35) and n²D_{$\text{3}\text{2}$,$\text{5}\text{2}$} (11 ? n ? 48) states of CsI have been measured with a thermionic detector. The absorption spectrum of molecular iodine was used as a reference giving us a total estimated accuracy of about 2 × 10^-7. Taking also into account the energies of the 7–11 ²S_{$\text{1}\text{2}$} and 5 and 6 ²D_{$\text{3}\text{2}$,$\text{5}\text{2}$} states measured by other authors and using an extended Ritz-formula we found the ionization limit to be E_i = 31406.468 ± 0.006 cm^-1.     

Determination of some atomic-state densities in an Xe-Br2 mixture

The atomic-state densities of the 6s[1 $\text{1}\text{2}$]⁰ metastable Xe energy level and of the 5s⁴P_{$\text{1}\text{2}$}, 5s⁴P_{$\text{3}\text{2}$} and 5s⁴P_{$\text{5}\text{2}$}Br energy levels in an Xe-Br₂ mixture have been determined as a function of current strength.     

Relativistic Hartree-Fock oscillator strengths for the lowest s→p and p→d transitions in the first few members of the Ag(I) and Au(I) isoelectronic sequences,with allowance for cope polarization

Relativistic, single-configuration Hartree-Fock oscillator strengths for the lowest ns²S_{$\text{1}\text{2}$}→np²P_{$\text{1}\text{2}$$\text{3}\text{2}$} and np²P_{$\text{1}\text{2}$$\text{3}\text{2}$}→nd²D_{$\text{3}\text{2}$$\text{5}\text{2}$} transitions in the first few members of the silver (n = 5) and gold (n = 6) isoelectronic sequences have been studied, both with and without allowance for core polarization. Core polarization is included by introducing a polarization potential in the one-electron Hamiltonian and by employing the corresponding correction for the dipole-moment operator in the transition matrix element. The results obtained are compared with available experimental data and the influence of core-polarization effects on oscillator strengths is discussed.     

Evidence for assignment of 14.0 MeV state in 11B from 10B(n,n)10B

The differential cross section and polarization for neutrons scattered from ¹⁰B have been measured at E_n = 2.63 MeV (E_x = 13.85 MeV). The results of this experiment and other available neutron scattering data in the range 1 < E_n < 4 MeV are interpreted through a single-level R-matrix calculation over the region 12 < E_x < 15 MeV. Based on this analysis the most probable J^π assignment for the 14.0 MeV level in ¹¹B is $\text{11}\text{2}{}^{\mathrm{+}}$. The anomaly near E_x = 13.1 MeV can only be explained in terms of two overlapping levels having assignments of ($\text{5}\text{2}$, $\text{7}\text{2}$)^? and ($\text{3}\text{2}$, $\text{5}\text{2}$, $\text{7}\text{2}$)⁺.     

Multiple quadrupolar spin echoes in the La-filled skutterudite LaOs4As12

We report experimental results of ¹³⁹La pulse NMR studies in LaOs₄As₁₂. Measurements have been performed on a powder sample obtained from high quality single crystals. For the first time the pattern of quadrupole echoes for ¹³⁹La nuclei (I=7/2) was obtained. All the allowed quadrupolar echoes expected for spin I=7/2 were observed at times t=(4/3)τ, (3/2)τ, (5/3)τ, 2τ, (5/2)τ, 3τ, 4τ. The presence of quadrupolar echoes is the fingerprint of the deviation from perfect cubic symmetry of the structure and can be used as a simple and fast test of the sample quality.     

Magnetic moments of the 12+ isomeric states in 194, 196, 198Pb

The g-factor of the 12⁺ isomeric state in lead isotopes with A = 194, 196, 198 was measured using the time-differential perturbed angular distribution method (TDPAD). The values obtained are respectively g(194) = ?0.158(6); g(196) = ?0.157(7); g(198) = ?0.144(11). A more precise determination of the 12⁺ level half-life is also made. The g-factprs of these nuclear states, which are described with v(i_{$\text{13}\text{2}$})^?2 as the main configuration, are surprisingly constant over a large mass range (between A = 206 and 194). A core polarization analysis explains this trend: the polarization induced on neutrons in i_{$\text{13}\text{2}$} orbit decreases with the mass number A (blocking effect), but a compensation is provided by the other spin-orbit partners f_{$\text{7}\text{2}$}-f_{$\text{5}\text{2}$} and P_{$\text{3}\text{2}$}-P_{$\text{1}\text{2}$}.     

Isomers in the N = 83 nucleus 149Dy

Energy levels in the N = 83 nucleus ¹⁴⁹Dy were studied by the reaction ¹⁵²Gd(α, 7n) at 106 MeV bombarding energy using in-beam γ-ray spectroscopy methods. The measurements identified three isomers in this nucleus, at 1073 keV (13 ± 3 ns), at 2700±150keV (5 μs < T_{$\text{1}\text{2}$} < 0.5 s), and above 3.5 MeV (50 ± 15 ns). The low-lying isomer is interpreted as i_{$\text{13}\text{2}$}. The configuration $\text{27}\text{2}$^?(πh_{$\text{11}\text{2}$}²)₁₀₊ ×vf_{$\text{7}\text{2}$} is suggested for the state at 2.7 MeV.     

Excitation of bromine by means of krypton in Kr-Br2 mixtures

The atomic-state populations of the 5s⁴P_{$\text{3}\text{2}$} and 5s⁴P_{$\text{1}\text{2}$} resonant levels of Br in a Kr-Br₂ mixture have been determined as functions of current strength. An increase in flux of Br emission lines passing into 5s levels has been observed.     

Experimental transition probabilities of some Xe(I) lines

Using the light absorption technique in a ¹³²Xe afterglow plasma, we have measured the relative transition probabilities for several xenon lines which have the metastable 6s[$\text{3}\text{2}$]₂ or the resonant 6s[$\text{3}\text{2}$]₁ states as their lowest transition level. Because the transition probabilities of the 8819 Å (6p[$\text{5}\text{2}$]₃ ? 6s[$\text{3}\text{2}$]²) and 8280 Å (6p[$\text{1}\text{2}$]₀ ? 6s[$\text{3}\text{2}$]₁) lines are relatively well known, we have chosen these as reference lines and have thus been able to determine the absolute values of the transition probabilities for 19 xenon lines corresponding to transitions from 6p, 6p′, 7p, 8p, 9p, 4f and 5f to 6s[$\text{3}\text{2}$]₂, and for four lines corresponding to the transitions 6p?6s[$\text{3}\text{2}$]₁.     

Relaxation of the 4G92 state of Nd3+ in LaCl3 and Nd3+ in La(Cl99.6Br0.4)3

The decay of the ⁴G_{$\text{9}\text{2}$} state of Nd³⁺ in LaCl₃ and La(Cl_99.6 Br_0.4)₃ was measured after pulsed laser excitation as a function of temperature. The decay rate is shown to depend besides the radiative transition on single-phonon relaxation between the states ⁴G_{$\text{9}\text{2}$} ($\text{μ =}\text{1}\text{2}$) and ⁴G_{$\text{9}\text{2}$} ($\text{μ =}\text{3}\text{2}$) and on multiphonon orbit-lattice relaxation from ⁴G_{$\text{9}\text{2}$} to ²G_{$\text{9}\text{2}$}. Partial substitution of Cl by Br only alters the radiative lifetime.     

Nuclear g-factor of the 172+ isomeric state in 63Cu

The nuclear g-factor of the 4498 keV $\text{17}\text{2}$⁺ isomeric state in ⁶³Cu was measured with the in-bearn perturbed angular distribution method, through the ⁶²Ni(α, p2nγ)⁶³Cu reaction, to be g_exp = 0.184 ± 0.012. This value is in good agreement with a semiempirical g-factor for the three-quasiparticle configuration [π2p_{$\text{3}\text{2}$}(v1f_{$\text{5}\text{2}$}, 1g_{$\text{9}\text{2}$})₇]_{$\text{17}\text{2}$⁺} calculated using the experimental single-particle g-factors of neighbouring nuclei. At the same time the internal magnetic field at the Cu nuclei in Ni metal was obtained to be B_int = ?46.6 ± 1.3 kG.     

Stark mixing spectroscopy in cesium

We present a new technique for selectively populating excited states which are inaccessible by dipole excitation from the ground state. The method uses a static electric field to introduce a component of a dipole-allowed state into the state of interest. We have applied the method to cesium to measure lifetimes and a Stark mixing coefficient. The results are $\text{τ(6}{}^2\text{D}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)=64(2) ns}$, $\text{τ(7}{}^2\text{D}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)=92.5(15) ns}$, and <6²D_{$\text{5}\text{2}$}|;ez |7²P_{$\text{3}\text{2}$}>/(E_7P?E_6D)=0.7(3)×10^?3 where is in kV/cm. 141     

Oscillator strengths of the first forbidden lines of rubidium

The oscillator strengths of the 5s-4d first forbidden lines of rubidium at 5165 Å were determined by performing CW tunable dye laser absorption measurements. Measured oscillator strengths of 8.06±0.48×10^-7 and 5.38±0.31×10^-7 for the ²D_{$\text{5}\text{2}$} and ²D_{$\text{3}\text{2}$} states, respectively, are compared with previously published values.     

Proton-neutron correlations in nuclei with N = 30

Structure of the nuclei with N = 30 and Z = 20–28 is investigated by the nuclear shell model within the proton-neutron configurations (1f_{$\text{7}\text{2}$})^z?20_p × (2p_{$\text{3}\text{2}$}, 2p_{$\text{case1}\text{2}$}, 1f_{$\text{case5}\text{2}$})²_n. Effective proton-neutron interactions determined by a least-squares fit to the observed spectra of N = 29 nuclei are adopted. Agreement of the calculated spectra with experimental spectra is satisfactory. Strong correlations between protons and neutrons break down the pairing scheme and lower the first J = 2 levels in doubly even nuclei, which is shown from the resultant wave functions. A relation between the shell model and collective rotational model is discussed concerning the calculated rotation-like spectrum of ⁵⁶Fe. Electromagnetic properties and spectroscopic factors of single-nucleon transfer reactions are calculated. They are in good agreement with experiments.     

Energy levels in 142Nd

The excited states of ¹⁴²Nd were studied by means of the decay of 40 sec ¹⁴²Pm and the ¹⁴²Nd(p, p') reaction via isobaric analog resonances. Approximately sixty levels of ¹⁴²Nd were observed below 5.3 MeV excitation, including several neutron particle-hole states excited strongly in (p, p') at f_{$\text{7}\text{2}$}, p_{$\text{3}\text{2}$}, p_{$\text{1}\text{2}$} and f_{$\text{5}\text{2}$} analog resonances. We have collected together all known energy levels in ¹⁴²Nd and have proposed J^π assignments for 22 excited states. We have also compared the experimental level spectrum (positive-parity states only) with a calculated one based on the shell model.     

Inelastic scattering and satellite fine structure in the high-resolution uv photoelectron spectrum of CS2

The outer valence region in CS₂ has been studied by high-resolution UV photpelectron Spectroscopy. The spectra reveal detailed vibrational structure in the X$\text{\$}\text{?}$²Π_g, A$\text{\$}\text{?}$²Π_u, B$\text{\$}\text{?}$²Σ⁺_u and C$\text{\$}\text{?}$²Σ⁺_g bands. Some of the fine-structure peaks in the X$\text{,}\text{?}$B$\text{\$}\text{?}$and C$\text{\$}\text{?}$bands are shown to be pressure-dependent. The reason for the pressure dependence is assumed to be inelastic scattering of electrons emitted in the adiabatic transitions. It is established that the two CI satellite bands present in the He(I)-excited spectrum contain vibrational structure.     

Determination of the atomic-state population in A Kr-Br2 mixture

The atomic-state populations of the 5s[1$\text{1}\text{2}$]° metastable level of Kr and of the 5s²P_{$\text{3}\text{2}$} resonant level of Br in a Kr-Br₂ mixture have been determined as functions of current strength. Occurrence of energy transfer from the Kr-level to the Br-level has been verified.     

Coherent information storage with photon echoes produced by switching electric fields

We demonstrate modified photon echoes in Eu³⁺:Y₂SiO₅ by controlling the inhomogeneous broadening of the optical transition in Eu³⁺. These modified photon echoes are shown to be capable of storing phase and amplitude modulation.     

Large angle production of stable particles heavier than the proton and a search for quarks at the CERN intersecting storage rings

Measurements have been performed on production of particles with mass 1.5 GeV/c² and charge $\text{?}\text{2}\text{3}$ for θ_lab = 62.5° and $\text{s}\text{= 53}\text{GeV}$. At p_T = 0.7 GeV/c the relative rate of production of antideuterons to π^? is (5 ± 1) × 10^?5. The deuteron to antideuteron ratio is 3.7 ± 1.2. No new stable particle has been amongst 0.7 × 10⁸ charged particles entering our detector.