The (7Li, 6Li) reaction on 28Si and 40Ca at E(7Li) = 45 MeV

Angular distributions for the (⁷Li, ⁶Li) reaction on ²⁸Si and ⁴⁰Ca to ground and excited states of ²⁹Si and ⁴¹Ca have been measured at $\text{E(}{}^7\text{Li}\text{) = 45}\text{MeV}$. The shapes of the angular distributions are well described by exact finite-range DWBA calculations. To test the sensitivity of the calculated angular distributions to the exit channel potential, calculations were made using a strongly absorbing ⁷Li potential for both the entrance and exit channels. This calculation produced as good a fit to the shape of the angular distributions as did calculations with a ⁶Li potential in the exit channel, even though ⁷Li and ⁶Li elastic scattering on these target nuclei are not very similar. However, the magnitudes of the calculated cross sections are sensitive to the choice of potentials, and agreement with light-ion spectroscopic factors is obtained when the more weakly absorbing ⁶Li potentials are used. The spectroscopic factors obtained from the ⁴⁰Ca(⁷Li, ⁶Li) reaction study are in good agreement with the extensive light-ion results showing that the absolute magnitude of the reaction is correctly predicted by exact finite-range DWBA calculations that use optical parameters determined from elastic-scattering data.     

Spectroscopy of A = 16 from 13C(6Li,t)16O

The ¹³C(⁶Li, t)¹⁶O reaction has been studied at 34 MeV. Selective population of narrow states is observed up to 21 MeV excitation in ¹⁶O. This reaction populates strongly both unnatural-and natural-parity states that have little or no ¹²C + α₀ width. The measured angular distributions are compared with Hauser-Feshbach and finite-range DWBA calculations. Reasonable agreement with the DWBA calculations is found for most of the states strongly populated. The widths of the narrow states populated in the 16–20 MeV excitation region are presented. Comparison of the present data with that from medium-energy inelastic scattering and other multiparticle transfer reactions is made.     

Classical and potential descriptions of 9Be+28Si and 9Be + 40Ca elastic scattering cross sections at E(9Be) = 45 and 60 MeV

The elastic scattering angular distributions for ⁹Be + ²⁸Si and ⁹Be + ⁴⁰Ca have been measured at ⁹Be bombarding energies of 45 and 60 MeV over an angular range in which $\text{σ}\text{σ}{}_{\mathrm{<mtext>R</mtext>}}$ varied from 1 (i.e. Rutherford scattering) to values ? 0.001. The measured cross sections are analyzed classically using Wegner plots and quantum mechanically using both an optical potential of Woods-Saxon form and a double-folding potential with a realistic nucleon-nucleon interaction. ⁹Be appears to exhibit somewhat different behaviour from both the lighter projectiles such as p and α and from its heavier neighbours such as ¹²C and ¹⁶O.     

New measurements of the masses of 15B and 19N

The neutron-rich nuclei ¹⁵B and ¹⁹N have been produced in reactions between ¹⁸O and ⁴⁸Ca. Mass excesses of 28.968 ± 0.025 MeV and 15.872 ± 0.020 MeV respectively were deduced from the reaction Q-values. These results are compared with previous measurements and theoretical predictions. Updated predictions using two different mass formulae are presented.     

The mass of 18C from a heavy ion double-charge-exchange reaction

The mass of ¹⁸C has been measured using the double-charge-exchange reaction ⁴⁸Ca(¹⁸O, ¹⁸C)⁴⁸Ti at an ¹⁸O energy of 112 MeV. The ¹⁸C ions were detected at the focal plane of a magnetic spectrometer. The mass excess of ¹⁸C was found to be 24.923 ± 0.030 MeV, and the first excited state was observed at an excitation energy of 1.62 ± 0.02 MeV. At the same time, an independent measurement of the mass excess of ¹⁷C was obtained from the ⁴⁸Ca(¹⁸O, ¹⁷C)⁴⁹Ti reaction, and the value 21.039 ± 0.020 MeV is in excellent agreement with an earlier measurement. The first excited state of ¹⁷C is at 295 ± 10 keV.     

Energy dependence of the 24Mg(16O, 12C)28Si reaction

Excitation functions for the reaction ²⁴Mg(¹⁶O, ¹²C)²⁸Si(g.s., 2⁺₁) were measured at 5°(lab) in the energy range 32 < E_c.m. < 49 MeV. Although the resonant structure, previously observed at lower energies, becomes progressively weaker, three new correlated maxima have been observed near E_c.m. = 37.5, 40.2 and 43.5 MeV. Angular distribution measurements at these energies yield spin assignments, from P²_j(cos θ) comparisons, of 27, 29 and 31, respectively. Attempts to find a consistent optical-model fit to the elastic scattering in the entrance channel and an exact finite-range DWBA fit to the four-nucleon transfer reaction in this energy range were unsuccessful. Such a failure is to be expected if strong couplings between the elastic channel and inelastic channels of either the initial or final system are important. The features of the resonance phenomena in the transfer reaction are discussed within a band crossing model framework.     

The mass and low-lying levels of 40Cl

The mass excess of the T_z = 3 nucleus ⁴⁰Cl has been determined using the ⁴⁰Ar(⁷Li, ⁷Be)⁴⁰Cl reaction. A value ?27.527 ± 0.035 MeV was obtained. A number of excited states of ⁴⁰Cl were a1so observed. In addition, the ⁴⁰Ar(¹¹B, ¹¹C)⁴⁰Cl and ⁴⁰Ar(¹¹B, ¹³N)³⁸S reactions were investigated. Excited states of ³⁸S were observed at 1.28 ± 0.04 and 3.38 ± 0.10 MeV.     

有机硅活性中间体的研究 II. 一些含环丙基的有机硅化合物的合成及其结构

用锂有机物的方法合成了四种含有环丙基有机硅化合物,对上述每种化合物中可能存在着的立体异构进行了分离和和构型测定。     

Large-angle enhancements in the 16O(6Li, α)18F reaction at 48 MeV

The elastic scattering of ⁶Li + ¹⁶O at 48 MeV has been measured and fitted with an optical model calculation. Measurements have been made of the ¹⁶O(⁶Li, α)F reaction at 48 MeV populating the 1⁺ g.s., 3⁺ 0.927 MeV and 5⁺ 1.122 MeV states in ¹⁸F. The data exhibit cross sections at large angles comparable to those at forward angles, and have been compared with exact finite-range DWBA calculations. Exchange contributions were included for the 1⁺ g.s. and were unable to account for the large-angle data. Calculated statistical compound nucleus cross sections were approximately a factor of 100 below the data. The same conclusions are reached for previously published data at 34 MeV.     

Elastic and inelastic scattering of 6Li and 7Li by 54Fe at E = 36–50 MeV

Detailed angular distributions for the elastic and inelastic scattering of ⁷Li at E = 36, 42, and 48 MeV and of ⁶Li at E = 38, 44, and 50 MeV by ⁵⁴Fe have been measured. It is not possible to describe both sets of data with the same set of optical-model parameters. The ratio of $\text{U}\text{W}$ is 0.8 for ⁷Li and 1.4 for ⁶Li at the strong absorption radius, implying stronger absorption for ⁷Li than for ⁶Li. No energy dependence in the optical-model parameters was necessary for either ⁶Li or ⁷Li. The inelastic scattering from the ⁵⁴Fe 2⁺, 1.41 MeV state was well described by the DWBA and the extracted deformation length (βR = 0.62) was the same for both ⁶Li and ⁷Li scattering. It was not possible to describe the ⁷Li projectile excitation data with collective-model DWBA calculations showing that more detailed calculations for the projectile excitation are necessary.