Structure and total strength of the magnetic dipole resonance in <Superscript>35</Superscript>Cl nuclei

The γ-decay of the resonance-like structure observed in the ³⁴S(pγ)³⁵Cl reaction in the energy range E _p = 1.0–3.0 MeV of accelerated protons was investigated. The M1 resonance on the ground and excited states of ³⁵Cl with E* = 1219 and 1763 keV was identified. The position of the center of gravity and total strength of the M1 resonance on ground state ³⁵Cl nucleus are determined. The position and total strength of the M1 resonance on the ground state in ³⁵Cl are explained taking into account pairing forces.     

<Superscript>1</Superscript>H NMR study of molecular dynamics of acetylcholine chloride

The longitudinal relaxation timeT ₁ and the second momentM ₂ of¹H nuclear magnetic resonance line in a wide temperature range have been measured for acetylcholine chloride. Two different types of the methyl groups reorientation occurred. The first type was the hindered rotation of the methyl group denoted as C(1)H₃ about the threefold symmetry axis. The second type was the reorientation of the trimethyl group-N(CH₃)₃ around the pseudo C₃^′ axis of C(6)-N(7) bond, which accompanied the standard C₃ motion of the methyl group. The Dunn-McDowell model was applied to analyze the dynamics observed.     

Theory of two-frequency excitation in<Superscript>14</Superscript>N NQR

A simple and effective technique for calculating the transient signals in three-level spin systems irradiated at one and two frequencies is described. All possible signals are presented and discussed. The application of the two-frequency excitation technique for the investigation of the inhomogeneity of the crystalline lattice is suggested.     

Longitudinal dynamics of <Superscript>197</Superscript>Au<Superscript>32+</Superscript> and <Superscript>197</Superscript>Au<Superscript>79+</Superscript> ions in NICA injection chain

The main objective of the NICA project developed at the Joint Institute for Nuclear Research (JINR) is to conduct experimental studies with colliding heavy ion beams in an energy range of 1–4.5 GeV/nucleonucleon with luminosity on the level of 1 × 10²⁷ cm⁻² s⁻¹. In this paper the operation regime of the collider injection chain providing the bunch with experimentally desirable parameters at the output of the Nuclotron is considered for gold ions as an example.     

Caesium and hydrated lead chlorates studied by35Cl NQR spectroscopy

Molecular dynamics of caesium and lead chlorates (hydrated form) has been studied by³⁵Cl nuclear quadrupole resonance (NQR) spectroscopy. The occurrence of only one resonance line for the two compounds in the whole temperature range studied testifies to the crystallographically equivalent positions of their molecules in elementary cells. The relaxation processes in the two chlorates have been found to be analogous to those in the other chlorates not undergoing phase transitions. Analysis of the temperature dependence of the spin-lattice relaxation time has indicated that at low temperatures the dominant relaxation mechanism consists of torsion vibrations (ClO₃⁻ anion libration), whereas at 260 K the hindered rotation of the chlorate ion about the threefold axis sets on and its activation energy is 50.0 kJ/mol. The temperature dependence of the resonance frequency for the two chlorates studied is best described by the Brown model extended over the low-temperature range, which indicates large anharmonicity of the vibrations.     

A Two-Spiral Flat Coil for Detecting <Superscript>14</Superscript>N NQR Signals

In the present article, the design of a two-spiral flat coil intended for detecting NQR signals is described. Results of calculations of its magnetic fields and field non-uniformities are presented for windings of different types. It is demonstrated that the two-spiral coil field is localized in the near-field zone and has more uniform structure than the field of the conventional spiral coil with the same radius and winding type. It is emphasized that the two-spiral coil has higher sensitivity than the analogous conventional flat coil. Results of experiments on detecting the ¹⁴ N NQR signal of urotropine C ₆ H ₁ N ₄ with this coil are presented. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 9, pp. 79–84, September, 2005.     

Density-constrained time-dependent Hartree-Fock calculation of <Superscript>16</Superscript>O + <Superscript>208</Superscript>Pb fusion cross-sections

We present a fully microscopic study of the ¹⁶O + ²⁰⁸Pb fusion using the density-constrained time-dependent Hartree-Fock theory. The calculated fusion cross-sections are in good agreement with the experimental data for the entire energy range indicating that the incorporation of dynamical effects is crucial in describing heavy-ion fusion.     

Studies of multi-nucleon transfer reactions in <Superscript>90</Superscript>Zr(<Superscript>18</Superscript>O,X) and <Superscript>90</Superscript>Zr(<Superscript>16</Superscript>O,X)

Multi-nucleon transfer reactions in ¹⁸O + ⁹⁰Zr and ¹⁶O + ⁹⁰Zr have been studied at an incident energy of 90 MeV. The energy spectra and angular distributions are measured. The data have been analyzed to obtain cross-section dependence on the number of nucleons transferred and on the ground-state Q-values. In the ⁹⁰Zr(¹⁸O, X); X = ¹⁶O, ^17,16,15,14N, ^14,13,12C, ^12,11,10B, ^10,9,7Be and ^7,6Li reactions, 2n and 2n-correlated transfer cross-sections are observed to be enhanced as compared to the ¹⁶O + ⁹⁰Zr reaction. A detailed comparison in the multi-particle stripping and elastic-scattering cross-section between these two systems are made in order to investigate the possible influence of the two valence neutrons in ¹⁸O nucleus. Diffractional model DWBA calculations, based on the direct surface transfer model, have been performed to understand the reaction mechanism of multi-nucleon transfer to continuum.Received: 12 September 2002, Revised: 24 September 2003, Published online: 27 January 2004PACS: 25.70.Hi Transfer reactions - 25.70.Bc Elastic and quasielastic scattering     

Isotopomer selective optimization of <Superscript>39</Superscript>K<Superscript>85</Superscript>Rb<Superscript>+</Superscript> and <Superscript>41</Superscript>K<Superscript>87</Superscript>Rb<Superscript>+</Superscript> using optimal control

We report on isotope selective three-photon ionization of two isotopomers of KRb by applying evolution strategies. The particularity of this experiment is based on the high resolution phase and amplitude modulation of the fs-laser pulses provided by a 2 × 640 pixel pulse shaper. The optimization in a closed feedback loop performed with spectrally broad pulses centered at 840 nm shows high enhancements of one isotopomer at the expense of the other isotopomer and vice versa. From the optimal laser field we aim to gain details about the selective ionization sequence and the wavepacket evolution on the involved vibrational states.     

Angular momentum dependence of quasifission dynamics in the reaction <Superscript>48</Superscript>Ca+<Superscript>244</Superscript>Pu

The quasifission dynamics in the reaction ⁴⁸Ca+²⁴⁴Pu is investigated in the framework of time-dependent Hartree-Fock (TDHF) theory. The calculations are performed in three-dimensional Cartesian coordinate without any symmetry restrictions. The full Skyrme energy functional is incorporated in our TDHF implementation. The quasifission dynamics is quite sensitive to the angular momentum of colliding system. The contact time of quasifission decreases as a function of angular momentum and then forms a plateau with small oscillations. The quasifission process is accompanied by an important multi-nucleon transfer. The quantum shell effect plays a crucial role in the mass and charge of quasifission fragments. The mass-angle distribution of the fragments is calculated, which can be compared directly with future experiments.     

Search for hyperdeformed structures populated in the <Superscript>37</Superscript>Cl+<Superscript>120</Superscript>Sn reaction by using EUROBALL III

The ridge structure with ΔE_γ=±30 keV, observed in the past in coincidence with protons emitted in the reaction 187 MeV ³⁷Cl +¹²⁰Sn and attributed to an hyperdeformed nuclear shape in ¹⁵²Dy, has been studied in a new experiment performed with the EUROBALL III array. The ridge is now observed in coincidence with transitions in the yrast superdeformed band of ¹⁵²Dy but no discrete rotational bands have been identified. Received: 7 February 2000     

<Superscript>4</Superscript>He<Superscript>3</Superscript>H<Superscript>2</Superscript>H three-body model of the <Superscript>9</Superscript>Be nucleus

Within the framework of the single-channel approximation, an {αtd} model of the ⁹ Be nucleus is presented. A comparative analysis of the t ⁶ Li wave functions describing relative motion of bound states constructed in {ααn} and {αtd} cluster representations is carried out on the example of calculations of the ⁹ Be(γ,t₀)⁶ Li process characteristics. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 85–89, January, 2008.     

Neutron single-particle structure of <Superscript>48</Superscript>Ca, <Superscript>50</Superscript>Ti, <Superscript>52</Superscript>Cr, <Superscript>54</Superscript>Fe,and <Superscript>56</Superscript>Ni nuclei

The change in the neutron single-particle structure of (1f?2p)-shell magic nuclei near the Fermi energy with an increase in the number of protons in the 1f _7/2 subshell from 0 for ⁴⁸Ca to 8 for ⁵⁶Ni has been investigated. Good agreement of the experimental and estimated values of the single-particle energies E _nlj of the bound states of neutrons in these nuclei with the results of calculations within the dispersive optical model is obtained.     

Nuclear level densities in <Superscript>47</Superscript>V, <Superscript>48</Superscript>V, <Superscript>49</Superscript>V, <Superscript>53</Superscript>Mn,and <Superscript>54</Superscript>Mn from neutron evaporation spectra

The spectra of neutrons from the (p, n) reactions on ⁴⁷Ti, ⁴⁸Ti, ⁴⁹Ti, ⁵³Cr, and ⁵⁴Cr nuclei were measured in the proton-energy range 7–11 MeV. The measurements were performed with the aid of a fast-neutron spectrometer by the time-of-flight method over the base of the EGP-15 tandem accelerator of the Institute for Physics and Power Engineering (IPPE, Obninsk). Owing to a high resolution and a high stability of the time-of-flight spectrometer used, low-lying discrete levels could be identified reliably along with a continuum section of neutron spectra. An analysis of measured data was performed within the statistical equilibrium and preequilibrium models of nuclear reactions. The relevant calculations were performed by using the exact formalism of Hauser-Feshbach statistical theory supplemented with the generalized model of a superfluid nucleus, the back-shifted Fermi gas model, and the Gilbert-Cameron composite formula for the nuclear level density. The nuclear level densities for ⁴⁷V, ⁴⁸V, ⁴⁹V, ⁵³Mn, and ⁵⁴Mn were determined along with their energy dependences and model parameters. The results are discussed together with available experimental data and recommendations of model systematics.     

Low-spin states in <Superscript>182</Superscript>Os and K<Superscript>π</Superscript> = 0<Superscript>+</Superscript>, 2<Superscript>+</Superscript> excited bands

Excited states in ¹⁸²Os were populated by the β⁺/EC decay of ¹⁸²Ir following mass separation. Gamma-ray and conversion electron spectroscopy techniques were employed. Monopole (E0) contributions were determined in transitions populating the ground-state band. A systematic study of the low-spin structures in the Os isotopes is presented and a detailed analysis in the framework of a microscopic configuration mixing approach is performed.     

Cosmogenic <Superscript>36</Superscript>Cl as a tool for dating permafrost ice

The method for dating permafrost based on the ³⁶Cl long-lived cosmogenic isotope is proposed. The production of ³⁶Cl in the atmosphere and lithosphere under the action of CRs is analyzed. It has been indicated that the ³⁶Cl/Cl isotopic ratio measured in ice is the measure of ice age. The results of permafrost sample dating with regard to the in situ production are presented. The method dating limit (2 Ma) has been calculated.     

Analysis of the normal optical,Michel and molecular potentials on the <Superscript>40</Superscript>Ca(<Superscript>6</Superscript>Li,d)<Superscript>44</Superscript> Ti reaction

Full finite-range (FFR) distorted-wave Born approximation (DWBA) method has been applied to analyse the angular distributions of cross-sections of the ⁴⁰Ca(⁶Li, d) ⁴⁴Ti reaction at 28 MeV incident energy for the 22 transitions involving both the bound and unbound states of ⁴⁴Ti by using the normal optical, Michel and molecular potentials. The extracted spectroscopic factors for the three optical potentials are compared with those of some previous studies of zero-range (ZR) calculations of the ⁴⁰Ca(⁶Li, d) ⁴⁴Ti reaction using the normal optical potential. The χ² values of all the levels are obtained for the three optical potentials to estimate the quality of the fits. Molecular and Michel potentials have been used for the first time to analyse the four-nucleon transfer reaction and it seems that the molecular potential fits the experimental data more satisfactorily for some of the states than the normal optical and Michel potentials.