The octupole giant resonance strength in 16O

Angular distributions for polarized proton inelastic scattering cross sections along with the analysing power for the reaction ${}^{16}\text{O}\text{(}\text{p}\text{,}\text{p}\text{′)}{}^{16}\text{O}{}^1\text{(2}{}^{\mathrm{?}}\text{, 8.88}\text{MeV}\text{)}$ at E_p=42.5, 44.0 and 49.3 MeV have been measured. A semidirect reaction analysis augments the evidence for octupole giant resonance strength in the 30 to 50 MeV energy region.     

Nuclear wave functions and mesonic exchange currents in the weak transition 16O(0+) ↔ 16N(0−)

We show that any deviation from the closed-core hypothesis for ¹⁶O(0⁺, g.s.) may strongly affect the theoretical ratio of the transition probabilities for the two inverse processes: ${}^{16}\text{O(0}{}^{\mathrm{+}}\text{, g.s.}\text{) →}{}^{16}\text{N(O}{}^{\mathrm{?}}\text{, 120 keV}\text{)}$ muon-capture) and ${}^{16}\text{N(0}{}^{\mathrm{?}}\text{, 120 keV}\text{) →}{}^{16}\text{O(0}{}^{\mathrm{+}}\text{, g.s.}\text{)}$ (beta-decay). As a consequence, the possible evidence for exchange currents in this transition must be reexamined. Preliminary calculations do not exclude a still large meson exchange effect.     

Structure of 0+ states in 18O

Analysis of spectroscopic factors obtained in single-nucleon transfer reactions leading to and from ¹⁸O yields two different sets of wave functions for the first three O⁺ states. One set of wave functions is in agreement with ¹⁶O(t, p)¹⁸O data for the three states-the other set is not. The wave functions that agree with the experimental data have the majority of the $\text{(s}\text{1}\text{2}\text{)}{}^2$ strength in the third O⁺ state.     

Interference between inelastic scattering and transfer in the scattering of 16O ON 17O

Angular distributions and an excitation function of the reaction ¹⁷O(¹⁶O, ¹⁶O)¹⁷O¹ ($\text{0.871,}\text{1}\text{2}{}^{\mathrm{+}}$) have been measured. The observed fine structure of the angular distributions cannot be explained by the dominating transfer process alone. An explanation is given in terms of interference between one-neutron transfer and inelastic scattering.     

A study of 3He capture in light nuclei

Excitation functions at θ = 90° have been measured for ${}^{16}\text{O}\text{(}{}^3\text{He}\text{, γ}{}_{\mathrm{0?2,\; 3?5,\; 6}}\text{)}{}^{19}\text{Ne}$, ${}^{15}\text{N}\text{(}{}^3\text{He}\text{, γ}{}_{\mathrm{0,\; 1?4}}\text{)}{}^{18}\text{F}\text{,}{}^{14}\text{N}\text{(}{}^3\text{He}\text{, γ}{}_{\mathrm{0,\; 1,2,3}}\text{)}{}^{17}\text{F}$, and ${}^{20}\text{Ne}\text{(}{}^3\text{He}\text{, γ}{}_{\mathrm{0\; +\; 1}}\text{)}{}^{23}\text{Mg}$, in the range E_{3He = 3–19 MeV}. The first reaction has also been studied at θ = 40°. Excitation functions at 90° have also been measured for and ${}^4\text{He}\text{(}{}^3\text{He}\text{, γ}{}_{\mathrm{0\; +\; 1}}\text{)}{}^7\text{Be}$ for E_3He = 19–26 MeV. Angular distributions have been measured for the first four reactions.For the most excitation functions, a broad peak is observed, several MeV wide, centred at about E_x≈ 20 MeV. Superimposed on this, in some cases, are narrower peaks, with width ≈ 1 MeV. Energies and widths have been extracted for all resonances.Cluster-model calculations have been carried out, using methods similar to those which have proved successful for low-lying states in A= 18–19 nuclei. No satisfactory correspondence with the present results was found. The shell model has been used to calculate Γ_3He and Γ_γ for 1?ω excitations in the final nuclei. These generally show good agreement with the trends of the experimental data. The results are consistent with the excitation of the giant dipole resonance in ³He capture, but much more weakly than in proton capture.     

Angular distribution of photoelectrons from atomic oxygen at 736 Å and 584 Å

The angular distributions of photoelectrons ejected in the process $\text{O}\text{(2}\text{p}{}^4{}^3\text{P}\text{) + hv →}\text{O}{}^{\mathrm{+}}\text{(2}\text{p}{}^3{}^4\text{S}\text{) +}\text{e}$ and $\text{O}{}^{\mathrm{+}}\text{(2}\text{p}{}^3{}^2\text{D}\text{) +}\text{e}$ have been measured at the 736 Å NeI resonance line and at the 584 Å HeI resonance line. The results show good agreement with theory.     

A resonant interpretation of gross structure in 12C + 12C and16O + 16O inelastic scattering

A barrier-top-resonance model calculation is found adequate to describe the gross structure behavior thus far observed in ${}^{12}\text{C}\text{+}{}^{12}\text{C and}{}^{16}\text{O}\text{+}{}^{16}\text{O}$ inelastic scattering excitation functions.     

The baryon ladder of the U(6,6)-symmetry

An unified classification of the Baryons is made with the help of the so-called Baryon ladder of U(6,6). For this reason a complete set of commuting operators (introduced in a previous paper), including the squares of the spin and the isotopic spin, their third projections, the hypercharge, the Baryon number and so on, is used. Multiplets of a nontraditional type are obtained, which are in good agreement with the experimental situation. A Baryon mass operator is introduced; it is diagonal in the particles. With its help series of mass formulas are obtained for Baryons with spin-parity $\text{(}\text{1}\text{2}\text{)}{}^{\mathrm{+}}$, $\text{(}\text{3}\text{2}\text{)}{}^{\mathrm{+}}$, $\text{(}\text{1}\text{2}\text{)}{}^{\mathrm{?}}$, $\text{(}\text{3}\text{2}\text{)}{}^{\mathrm{?}}$, $\text{(}\text{5}\text{2}\text{)}{}^{\mathrm{?}}$ and they are in a very good agreement with the experiment.     

Spin measurements and reaction mechanism in the inelastic scattering of 18O on 12C

The alpha-decay of states in ¹⁸O have been studied in the inelastic scattering reaction ${}^{12}\text{C}\text{(}{}^{18}\text{O}\text{,}{}^{18}\text{O}{}^1\text{→}{}^{14}\text{C}\text{-α)}$ at 82 MeV. The double differential cross sections have been analysed with a strong absorption model. A systematic dependence of emission angle on spin is observed, allowing the determination of the transferred angular momentum.     

Role of the 12C-core exchange in the 16O-12C elastic scattering

The exchange of the ¹²C core is taken into account explicitly in ¹⁶O-¹²C elastic scattering to explain the backward rise of the angular distributions. The equation for the relative motion of the colliding particles contains the non-local kernel due to the exchange effect. The equation is solved by the iterative method. The angular distributions are calculated at $\text{E}{}_{\mathrm{<mtext>L</mtext>}}\text{(}{}^{16}\text{O}\text{) = 24, 42, 65}\text{and}\text{80}\text{MeV}$. The results are compared with those of finite-range DWBA calculations. The effects of the multi-step transfer process, the α¹ transfer process and of the non-orthogonality term are studied. The equivalent local potential to the non-local kernel is derived under the adiabatic approximation. The resulting local potential shows the parity dependence with the exponentially decreasing behaviour at the asymptotic regions and is found to describe the low-energy scattering phenomena quite well.     

The separation of proton and deuteron spin-dependent effects in the 116Sn(d,p)117Sn reaction

The cross section, vector analyzing power, and proton polarization have been measured for the l_n = 0 reaction ¹¹⁶Sn(d, p)¹¹⁷Sn(g.s.) at 8.22 MeV. In addition, cross section and analyzing power data have been obtained at 8.22 MeV for ${}^{116}\text{Sn}\text{(}\text{d}\text{,}\text{d}\text{)}{}^{116}\text{Sn}$ and for ¹¹⁶Sn(d, p)¹¹⁷Sn leading to excited states of ¹¹⁷Sn at 0.159, 0.317, 1.020, 1.179, 1.308 and 1.497 MeV. The cross section and analyzing power for ${}^{117}\text{Sn}\text{(}\text{p}\text{,}\text{p}\text{)}\text{Sn}$ and for ${}^{117}\text{Sn}\text{(}\text{p}\text{,}\text{d}\text{)}{}^{116}\text{Sn}$ leading to the 1.294 MeV state of ¹¹⁶Sn have also been measured at 12.91 MeV. The data for ¹¹⁶Sn(d, p)¹¹⁷Sn(g.s.) have been used to separate the contributions to the analyzing power arising from spin-dependent forces in the proton and deuteron channels. A similar analysis is presented for an $\text{l}{}_{\mathrm{n}}\text{= 0}{}^{90}\text{Zr}\text{(}\text{d, p}\text{)}{}^{91}\text{Zr}$ transition at 11 MeV. Optical-model analyses have been performed for the elastic scattering data. The reaction data have been compared with distorted-wave calculations in order to investigate the validity of various deuteron potentials, as well as to extract spectroscopic information.     

Coupling constants for several light nuclei from a dispersion analysis of nucleon and deuteron scattering amplitudes

A forward dispersion relation cannot be applied to charged particle scattering amplitudes unless the influence of the Coulomb interaction is explicitly considered. Earlier studies have shown how Coulomb effects can be taken into account when direct (s-channel or bound-state) poles are investigated. In this paper we extend the Coulomb modification to include I = 0 exchange (u-channel) processes as well. We then apply a forward dispersion relation to empirical d + α, p + d and n + d elastic scattering amplitudes which contain both direct and exchange poles with and without Coulomb effects. We obtain detailed and model-independent information on the following vertices: ⁶Li-α-d (S- and D-state) ⁴He-d-d, ³He-d-p, ³H-d-n and d-p-n. From the coupling constants we calculate the asymptotic normalization (spectroscopic factors) C²₁ of the corresponding cluster wave functions, which become: $\text{C}{}^2{}_0\text{(}{}^6\text{Li}\text{, α}\text{d}\text{) = 4.62 ± 0.23}$, $\text{C}{}^2{}_2\text{(}{}^6\text{Li}\text{, α}\text{d}\text{) = (1 ± 6) × 10}{}^{\mathrm{?4}}$, C²₀(α, dd) < 2, $\text{C}{}^2{}_0\text{(}{}^3\text{He, dp}\text{) = 3.5 ± 0.4}$, $\text{C}{}^2{}_0\text{(}{}^3\text{H, dn}\text{) = 2.6 ± 0.3}\text{and}\text{C}{}^2{}_0\text{(}\text{d, np}\text{) = 1.66 ± 0.1}$.     

Study of the reactions 118Sn(d,t) and98Mo(d,t): (I). Spectroscopy of 117Sn and 97Mo

The vector analyzing power and differential cross section have been measured at a deuteron energy of 12.0 MeV for ${}^{118}\text{Sn}\text{(}\text{d}\text{,}\text{t}\text{)}$ transitions to six states of ¹¹⁷Sn (E_x = 0.0, 0.16, 0.31, 0.71, 1.02 and 1.18 MeV), for ${}^{98}\text{Mo}\text{(}\text{d}\text{,}\text{t}\text{)}$ transitions to eight states of ⁹⁷Mo (E_x = 0.0, 0.68, 0.72, 0.89, 1.12, 1.28, 2.39 and 2.52 MeV), and for ${}^{118}\text{Sn}\text{(}\text{d}\text{,}\text{d}\text{)}\text{and}{}^{98}\text{Mo}\text{(}\text{d}\text{,}\text{d}\text{)}$. Deuteron optical model potentials were obtained from analysis of the elastic scattering measurements, and were used in a DWBA analysis of the $\text{(}\text{d}\text{,}\text{t}\text{)}$ results. Comparison of the measurements and DWBA predictions for σ(θ) and for iT₁₁(θ) allows unambiguous determination of tl_n and j_n for all ¹¹⁸Sn(d, t) and most ⁹⁸Mo(d, t) transitions. Differences in the triton energy relative to the Coulomb barrier cause marked qualitative differences in the measured cross sections and analyzing powers between ${}^{118}\text{Sn}\text{(}\text{d}\text{,}\text{t}\text{)}\text{and}{}^{98}\text{Mo}\text{(}\text{d}\text{,}\text{t}\text{)}$ transitions of the same l_n and j_n.     

H− Formation in proton-metal collisions

Negative hydrogen ion formation is studied by scattering protons from a cesiated tungsten (110) surface. The primary energy ranges from 50 to 400 eV. The angle of incidence is 70° with respect to the surface normal. A maximum conversion efficiency $\text{H}{}^{\mathrm{?}}\text{(H}{}^{\mathrm{?}}\text{+ H}{}^0\text{)}$ of 67% is measured. The measurements can be described in terms of the probability model. The perturbation of the H^? ion by the metal is described within first order perturbation theory. A reasonable agreement between theory and experiment is obtained.     

Stereoelectronic properties of photosynthetic and related systems: Ab initio configuration interaction calculations on the ground and lower excited singlet and triplet states of magnesium chlorin and chlorin

Ab initio configuration interaction wavefunctions and energies are reported for the ground state and many low-lying singlet and triplet states of magnesium chlorin and chlorin, and are employed in an analysis of the electronic absorption spectra of these systems.In chlorin, the calculated visible spectrum consists of two ${}^1\text{(π, π}{}^1\text{)}$ states, the lower energy, y-polarized state exhibiting moderate absorption intensity in contrast to the very weak absorption of the higher energy x-polarized state. The configurational composition of both states is well described by the four-orbital model. Five ${}^1\text{(π, π}{}^1\text{)}$ states are responsible for the Soret band envelope. A moderately intense y-state lies under the low energy edge of the band envelope, while two x-polarized states of moderate and strong intensity, respectively, are responsible for the band maximum. The final two ${}^1\text{(π, π}{}^1\text{)}$ states lie at the high energy edge of the Soret band and introduce a measure of asymmetry into the band envelope. Two ${}^1\text{(n, π}{}^1\text{)}$ states of very weak oscillator strength are also found in this region of the spectrum. All the Soret states are of complex configurational composition, and several of the higher lying states contain contributions from doubly excited configurations.The calculated visible spectrum of magnesium chlorin also consists of two ${}^1\text{(π, π}{}^1\text{)}$ states, with the weakly absorbing x-polarized state lying approximately 200 cm^?1 lower in energy than the moderately intense y-polarized state. The configurational composition of both states is well described by the four-orbital model. Four ${}^1\text{(π, π}{}^1\text{)}$ states constitute the bulk of the intensity in the Soret band envelope. In distinction to chlorin, the moderately intense ${}^1\text{(π, π}{}^1\text{)}$ state at the low energy edge of the band envelope is x-polarized. Two intense ${}^1\text{(π, π}{}^1\text{)}$ states of y- and x-polarization, respectively, constitute the band maximum region, and a single x-polarized state of moderately strong intensity can be assigned to the high energy shoulder of the band envelope. Two other weakly absorbing ${}^1\text{(π, π}{}^1\text{)}$ states are also found in this region, along with another weakly absorbing state of mixed in-plane and out-of-plane polarization. No clearly defined ${}^1\text{(n, π}{}^1\text{)}$ states are observed. As was the case for chlorin, all the Soret states are of complex configurational composition, and some of the higher energy states contain significant contributions from doubly excited configurations.Chlorin and magnesium chlorin both possess three ${}^3\text{(π, π}{}^1\text{)}$ states which lie below S₁ and a single ${}^3\text{(π, π}{}^1\text{)}$ which lies slightly above S₂. All four of the low-lying ${}^3\text{(π, π}{}^1\text{)}$ states in each molecule are well described by the four-orbital model, with T₁ being essentially a single configuration in each case. The remainder of the ${}^3\text{(π, π}{}^1\text{)}$ states are clustered in the same energetic region as the comparable ${}^1\text{(π, π}{}^1\text{)}$ Soret states, with comparably complex configurational compositions.Dipole moments and charge distributions for low-lying singlet and triplet states are also reported, and are used to rationalize chemical reactivity characteristics.     

A study of the 29,30Si(α, d)31,32P and the 29,30Si(d, α)27,28 Al reactions

The ${}^{\mathrm{29,30}}\text{Si}\text{(α,}\text{d}\text{)}{}^{\mathrm{31,32}}\text{P}$ reactions have been studied at a beam energy of 25 MeV and the ${}^{\mathrm{29,30}}\text{Si}\text{(}\text{d}\text{, α)}{}^{\mathrm{27,28}}\text{Al}$ reactions have been studied using a 12.3 MeV tensor polarised deuteron beam. The data have been analysed using the microscopic DWBA. Three representations of the nucleon-nucleon interaction have been compared by incorporating the appropriate spectroscopic amplitudes for two nucleon transfer obtained from shell model calculations, in the microscopic form factor.     

16O(p,α0)13N cross-section measurements

Total cross sections for the ${}^{16}\text{O}\text{(}\text{p}\text{, α}{}_0\text{)}{}^{13}\text{N}$ reaction have been measured by observation of the positron decay of the residual ¹³N nuclei. These cross sections, covering the c.m. energy range 5.4 ≦ E ≦ 9.9 MeV, allow determination of reaction rates of astrophysical interest at temperatures in the neighborhood of 4 × 10⁹°K.     

On production of large transverse momentum hadrons on nuclei

It is shown that multipole pomeron cuts can lead to the inclusive cross-section dependence $\text{(}\text{ω}\text{d}{}^3\text{σ}\text{d}\text{p}{}^3\text{)A ～ A}{}^{\mathrm{\gamma (p\perp )}}$, $\text{γ(p⊥) ?}\text{4}\text{3}$ at large p⊥, due to the hard scattering of partons from different pomeron ladders.     

Polarization transfer effects in (p, n reactions on light nuclei at θ = 0°

Transverse polarization transfer coefficients K_y^y′ have been measured at a reaction angle of 0° for the reactions ${}^9\text{Be}\text{(}\text{p}\text{,}\text{n}\text{)}{}^9\text{B}\text{,}{}^{11}\text{C}$ and ${}^{13}\text{C}\text{(}\text{p}\text{,}\text{n}\text{)}{}^{13}\text{N}$. In the energy range covered by these measurements, i.e., from about 7 to 15 MeV, the K_y^y′(0) values are generally positive. The polarization transfer excitation functions all show considerable structure which we largely attribute to compound nucleus effects.     

Neutron-proton shell model multiplets in 88Y and 90Y from a study of the (α, nγ) reaction

The non-selective nature of the (α, nγ) reaction has been used to complement information from charged-particle reactions on the level structure of ⁸⁸Y and ⁹⁰Y. The γ-ray spectra were recorded with a 25 cm³ Ge(Li) detector at 90° to the beam using primarily targets of ⁸⁵Rb₂CO₃ and ⁸⁷Rb₂CO₃ and α-particle energies of 11.8, 12.2 and 13.0 MeV. The resulting transitions were accommodated in level schemes that involved primarily the following shell model configurations: $\text{(π}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)}{}^1\text{(ν}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?1}}$, $\text{(π}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?1}}\text{(ν}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^1$, $\text{(π}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)}{}^1\text{(ν}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?1}}$, $\text{(π}\text{f}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?1}}\text{(ν}\text{g}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^{\mathrm{?1}}$ in ⁸⁸Y and $\text{(π}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)}{}^1\text{(ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}{}^1$, $\text{π}\text{g}\text{(}{}_{\mathrm{<mtext>9</mtext><mtext>2</mtext>}}\text{)}{}^1\text{(ν}\text{d}{}_{\mathrm{<mtext>5</mtext><mtext>2</mtext>}}\text{)}{}^1$,$\text{(π}\text{p}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{)}{}^1\text{(ν}\text{s}{}_{\mathrm{<mtext>1</mtext><mtext>2)</mtext>}}\text{)}{}^1$ in ⁹⁰Y.