The dependence with energy and target mass of friction coefficients $K$ deduced from ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$-induced reaction data are analyzed within the one-body energy dissipation formalism. The observed systematics for $K$ are explained as arising from changes in the effective reaction geometry. A unified expression for the angular distributions of the projectilelike products from these reactions is deduced.

NUCLEAR REACTIONS $X({}_{}{}^{16}{}_{}{}^{}\mathrm{O}, Y)$, $X={}_{}{}^{12}{}_{}{}^{}\mathrm{C}, {}_{}{}^{27}{}_{}{}^{}\mathrm{Al}, {}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}, {}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$, $Y=\mathrm{projectilelike}$ fragments ($Z=3-9\mathrm{}$), $E=100-315\mathrm{}$ MeV. Dependence of frictional coefficients on target mass and $E$ studied. Mass-flow rate deduced. Unified expression for slopes of $\sigma (E, Z, \theta )$ found.

We have reanalyzed the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$+${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ elastic scattering data at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=35.7\mathrm{}$ MeV with both full and restricted model-independent searches and we find potentials which do not fall within the error bars of a spline model analysis previously published in this journal. The potentials we find are much smoother, departing only slightly in the surface from a Woods-Saxon shape. Error bars determined for potentials are of restricted significance.

NUCLEAR REACTIONS ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$+${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ elastic scattering, $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=35.7\mathrm{}$ MeV; optical model analyses with full and restricted spline model representation.

A set of proton spin observables has been measured for the inelastic transitions to the $3^{-}$ (3.73 MeV) and $5^{-}$ (4.48 MeV) states in the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}(p, p^{\prime }){}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ reaction and for the $3^{-}$ (2.61 MeV) state in the ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}(p, p^{\prime }){}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ reaction at 497 MeV. The interval of laboratory scattering angles was 6 to 20° for ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ and 2.5 to 14° for ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$. Comparison of these observables reveals that they satisfy relations analogous to those valid in the elastic scattering of spin ½ and spin 0 objects. The origin of these observed relations is explained.

NUCLEAR REACTIONS Relations between spin observables in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}(p, p^{\prime }){}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}(p, p^{\prime }){}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ at 500 MeV.

The ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ reaction has been studied from 20.0 to 32.4 MeV (c.m.) in steps of 200 keV. Twenty-one $\gamma$-ray excitation functions have been investigated, seven of them as binary, and fourteen as fusion-evaporation exit channels. Most of the excitation functions display structures which are strongly correlated. In particular, a one-to-one correspondence between the peaks of summed binary and summed fusion-evaporation excitation functions has been established. A comparison with the ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ system leading to the same ${}_{}{}^{30}{}_{}{}^{}\mathrm{Si}$ composite nucleus is presented.

NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({}_{}{}^{18}{}_{}{}^{}\mathrm{O}, x)$; $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=20-32.4\mathrm{}$ MeV, measured $I_{\gamma }$. Deduced correlated structures.

A helium jet system and the ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}({}_{}{}^3{}_{}{}^{}\mathrm{He}, p4n){}_{}{}^{22}{}_{}{}^{}\mathrm{Al}$ reaction at 110 MeV have been used to discover the first odd-odd $T_z=-2\mathrm{}$ nuclide ${}_{}{}^{22}{}_{}{}^{}\mathrm{Al}$ ($t_{\frac{1}{2}}\sim 70$ ms), which has been predicted to lie on the edge of stability. Beta-delayed protons from its decay establish the mass excess of the lowest $T=2\mathrm{}$ state in ${}_{}{}^{22}{}_{}{}^{}\mathrm{Mg}$ as 13.650 ± 0.015 MeV corresponding to an excitation energy of 14.044 MeV.

RADIOACTIVITY ${}_{}{}^{22}{}_{}{}^{}\mathrm{Al}$ from ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}({}_{}{}^3{}_{}{}^{}\mathrm{He}, p4n)$; measured $\beta$-delayed protons, $T_{\frac{1}{2}}$; deduced branching and $\sigma$; derived mass excess of lowest $T=2\mathrm{}$ state in ${}_{}{}^{22}{}_{}{}^{}\mathrm{Mg}$.

Within the framework of many-body theory, a generalized Hartree-Fock equation is derived assuming a periodic density fluctuation. In a one-dimensional model, self-consistent solutions are calculated. A band structure of the single-particle spectrum and several minima of the total energy appear as novel features.

NUCLEAR MATTER Static density fluctuations, generalized Hartree-Fock method.

The antisymmetric spin-orbit interaction proposed for $\mathrm{sd}$-shell nuclei is investigated. It is shown that the important contribution of the antisymmetric spin-orbit component to the effective interactions is to give the proper centroid energy of the $d_{\frac{5}{2}}-d_{\frac{3}{2}}$ interactions which plays a crucial role in reproducing the excited band spectra of $A=18-24\mathrm{}$ nuclei. Also proposed is an empirical effective interaction without the antisymmetric spin-orbit component to reproduce the observed spectra of light $\mathrm{sd}$-shell nuclei.

NUCLEAR STRUCTURE ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$; calculated levels; $0d_{\frac{5}{2}}-1\mathrm{}{s}_{\frac{1}{2}}-0\mathrm{}{d}_{\frac{3}{2}}$ shell model. Effective interactions; Kuo, Chung-Wildenthal, and NOALS; antisymmetric spin-orbit component.

The lifetimes of states in ${}_{}{}^{152}{}_{}{}^{}\mathrm{Gd}$ have been measured by the Doppler-shift recoil-distance technique. Half-lives determined for the $2^{+}$, $4^{+}$, $6^{+}$, $2^{+\text{'}}$, and $0^{+\text{'}}$ states are 34.2±1.5, 7.3±0.4, 2.5±0.5, 7.3±0.6, and 37±8 ps, respectively. These states were Coulomb excited with 147-MeV ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ ions and measurements were performed in coincidence with the back-scattered projectiles. Comparisons of the experimental values with calculations from the rotational, vibrational, dynamic deformation, boson expansion, and interacting boson models show that the predictions of the latter two theories provide a reasonable overall description of this nucleus, but there are some discrepancies in interband transition strengths. In the course of this work the half-life of the $6^{+}$ state of ${}_{}{}^{156}{}_{}{}^{}\mathrm{Gd}$ was also redetermined as 16.7±0.6 ps.

NUCLEAR REACTIONS ${}_{}{}^{152}{}_{}{}^{}\mathrm{Gd}({}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}, {}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}_{}^{\prime }{}_{}{}^{}, \gamma )$, $E=147.2\mathrm{}$ MeV; measured lifetimes of $2^{+}$, $4^{+}$, $6^{+}$, $2^{+\text{'}}$, and $0^{+\text{'}}$ states; deduced $B\left(E2\mathrm{}\right)\mathrm{}$ values, compared with theory.

Inelastic scattering of ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$+${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ was investigated at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=42.85\mathrm{}$ MeV in order to study the influence of coupled channels effects. Angular distributions were measured in the angular range ${\theta }_{\mathrm{lab}}=5\mathrm{}°-45\mathrm{}°$ for elastic scattering and inelastic excitation of the $3^{-}$(3.737 MeV), $2^{+}$(3.905 MeV), $5^{-}$(4.492 MeV) states in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ and the $2^{+}$(1.982 MeV) and $3^{-}$(5.098 MeV) states in ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$. The results are compared to distorted-wave Born approximation and coupled channel calculations employing collective form factors. The improvements of the coupled channel predictions over those of the distorted-wave Born approximation are less dramatic than observed previously for ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$+${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$. With the exception of the ground state transition, the spectroscopic factors for the one-neutron-transfer reaction ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$(${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$)${}_{}{}^{41}{}_{}{}^{}\mathrm{Ca}$ are in good agreement with those observed in light ion induced reactions.

NUCLEAR REACTIONS ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$(${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$)${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, $E_{\mathrm{lab}}=62.14\mathrm{}$ MeV; measured $\sigma \left(\theta \right)$, elastic and inelastic scattering; (${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$) and (${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$) reactions; optical model, DWBA, CC calculations; deduced deformation lengths and spectroscopic factors.

Using a random-matrix model to describe the coupling between a collective nuclear variable and the other (intrinsic) degrees of freedom and the functional integral approach, we derive and discuss the mass (or inertial) parameter for the collective variable in the high-temperature limit. The calculations are performed by using both a fixed and the adiabatic basis for the intrinsic states, and the results are given for both the weak- and the strong-coupling limit between collective and intrinsic degrees of freedom. The results are evaluated numerically, discussed, and compared with the formulas obtained from the cranking model and linear response theory.

NUCLEAR REACTIONS Random-matrix model applied to heavy ions and fission. Collective mass parameter using a fixed and an adiabatic intrinsic basis of states. Path integral method.

We extend the applicability of the density matrix expansion to a complex effective interaction depending both on the density and the kinetic energy density. A detailed study of the kinetic energy density dependence of the density matrix expansion coefficients is given. The corresponding energy density has a parametrized form which is tested in the calculation of the optical potential of the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$+ ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ system at several energies. Exact results are well reproduced by the complex density matrix expansion.

NUCLEAR REACTIONS Density matrix expansion for a complex effective interaction; application to heavy ion optical potential.

The decay of compound nuclei formed at high excitation and angular momentum in ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ bombardment of ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$, ${}_{}{}^{194,198}{}_{}{}^{}\mathrm{Pt}$, ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$, and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ has been investigated in a coherent program of experiments and statistical model analysis. The measured decay properties include absolute cross sections for fusion and for all major competing decay modes, fission-fragment angular distributions, charged-particle energy spectra, and (${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, $\mathrm{xn}$) residue mass distributions. The measurements are compared with highly constrained calculations in which all nuclear structure parameters are fixed to values consistent with the rotating-liquid-drop and noninteracting Fermi-gas models. Possible ambiguities in interpreting the experimental results, and the likely influence of neglected effects on the statistical model calculations, are explored. In order to obtain good quantitative agreement with all measurements it is necessary to simulate in the calculations the effects of preequilibrium nucleon emission in the early stages of the decay, and it is furthermore helpful to allow the collective enhancements of deformed-nucleus level densities to fade out with increasing temperature. Within existing uncertainties in the statistical model treatment, reproduction of the experimental results does not require any appreciable macroscopic or microscopic corrections to the nuclear structure input parameters. Several experimental methods for studying more selectively the fission and particle decay of low-excitation, high-spin nuclei, and thereby enhancing sensitivity to microscopic structure contributions, are suggested.

NUCLEAR REACTIONS Fusion, fission, particle emission for ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$+${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$, ${}_{}{}^{194,198}{}_{}{}^{}\mathrm{Pt}$, ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$, ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$, $E\left({}_{}{}^6{}_{}{}^{}\mathrm{Li}\right)=74.8, 84.2, 94.4$ MeV; measured energy spectra, ${\sigma }_{\mathrm{tot}}$, $\sigma \left(\theta \right)$ for fission and inclusive charged-particle emission, ${\sigma }_{\mathrm{tot}}$ and mass distribution of residual nuclides for (${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, $\mathrm{xn}$) reactions; compared measurements with statistical model calculations incorporating simple macroscopic structure predictions, deformed-nucleus level densities, "hot-spot" simulation of preequilibrium nucleon emission; discussed theoretical uncertainties in statistical model analysis, possibilities for experiments with enhanced sensitivity to microscopic structure.

Inappropriate formulations for nuclear level densities, based in part on an assumption of spherical symmetry, have often been employed in statistical model calculations of the competition between decay modes of nuclei at high spin and excitation. We investigate the influence on such calculations of nuclear deformation effects in the level densities, at both the saddle-point shapes relevant to fission and the most probable shapes reached in particle evaporation. The deformation effects are included in a Fermi-gas formalism in two stages, first assuming complete independence of rotational and intrinsic degrees of freedom, and subsequently allowing for a deformation-dependent cutoff with increasing temperature in the collective enhancement of the level densities. The latter effect gives rise, in the absence of shell and pairing corrections, to a progressive increase with increasing temperature in the most probable daughter-nucleus deformation for particle emission. The most significant effects of the deformed-nucleus level densities on calculated decay properties for ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$+${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$→${}_{}{}^{203}{}_{}{}^{}\mathrm{Pb}$, at several bombarding energies, are an increase in the cross section and a decrease in the anisotropy for fission fragments. Ambiguities in the details of the collective cutoff yield a sizable uncertainty in the quantitative extent of the fission enhancement. Relative measurements for different entrance channels to the same compound nucleus which may be sensitive to the collective cutoff are illustrated by calculations for ${}_{}{}^{22}{}_{}{}^{}\mathrm{Ne}$+${}_{}{}^{180}{}_{}{}^{}\mathrm{Hf}$ vs ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$+${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ fusion-fission.

NUCLEAR REACTIONS Fission-evaporation competition in decay of ${}_{}{}^{203}{}_{}{}^{}\mathrm{Pb}$ from high excitation and angular momentum. Statistical model calculations for deformed nuclei incorporate collective level density enhancements which fade with increasing temperature.

The high-spin states of ${}_{}{}^{123,125,127}{}_{}{}^{}\mathrm{I}$ have been investigated via the ${}_{}{}^A{}_{}{}^{}\mathrm{Sn}({}_{}{}^6{}_{}{}^{}\mathrm{Li}, 3n){}_{}{}^{A+3\mathrm{}}{}_{}{}^{}\mathrm{I}$ reactions to study the collective properties of the odd-mass I isotopes. In-beam measurements of $\gamma$-ray excitations, $\gamma -\gamma$ coincidences, $\gamma$-ray angular distributions, and pulsed beam-$\gamma$ timing were performed with Ge detectors to determine level energies, decay schemes, $\gamma$-ray multipolarities, $J^{\pi }$ assignments, and lifetime information. A similar study of the ${}_{}{}^{117,119,121}{}_{}{}^{}\mathrm{I}$ isotopes is reported in the following paper. Two collective features have been identified in these odd-mass I nuclei. Systematic $\Delta J=1\mathrm{}$ bands built on low-lying ${\frac{9}{2}}^{+}$ proton-hole (4p-1h) states were observed. The ${\frac{9}{2}}^{+}$ bandheads, that involve the excitation of a $1g_{\frac{9}{2}}$ proton across the $Z=50\mathrm{}$ shell, drop to very low energies near the middle of the neutron shell. The properties of the ${\frac{9}{2}}^{+}$ proton-hole states for all of the odd-mass I isotopes are presented and related to the systematic information for the proton-hole states in the entire $Z>\mathrm{}50\mathrm{}$ transition region. Systematic $\Delta J=2\mathrm{}$ bands built on ${\frac{11}{2}}^{-}$ ($1h_{\frac{11}{2}}$ quasiproton) states, on ${\frac{7}{2}}^{+}$ ($1g_{\frac{7}{2}}$ quasiproton) states, and on ${\frac{5}{2}}^{+}$ ($2d_{\frac{5}{2}}$ quasiproton) states were also observed. The $\Delta J=2\mathrm{}$ band spacings generally follow the spacings of the Te-core ground-state bands with the exception of the ${\frac{11}{2}}^{-}$ $\Delta J=2\mathrm{}$ bands, for which the spacings decrease significantly relative to those for the Te cores as $A$ decreases. These systematic properties are discussed in terms of several theoretical approaches to the onset of collectivity in transitional nuclei. An isomer at 2660 keV in ${}_{}{}^{123}{}_{}{}^{}\mathrm{I}$ was observed to have a mean lifetime $\tau =38\mathrm{}\pm 3$ ns.

NUCLEAR REACTIONS ${}_{}{}^{120-124}{}_{}{}^{}\mathrm{Sn}({}_{}{}^6{}_{}{}^{}\mathrm{Li}, 3n){}_{}{}^{123-127}{}_{}{}^{}\mathrm{I}$; measured $\gamma -\gamma$ coincidences, $\gamma (E, \theta , t)$; deduced level schemes in odd-mass ${}_{}{}^{123-127}{}_{}{}^{}\mathrm{I}$, $\gamma$ multipolarities, $J^{\pi }$, $T_{\frac{1}{2}}$. Enriched targets, Ge(Li) detectors.

The high-spin states of ${}_{}{}^{117,119,121}{}_{}{}^{}\mathrm{I}$ have been investigated by in-beam $\gamma$-ray spectroscopy via the ${}_{}{}^A{}_{}{}^{}\mathrm{Sn}({}_{}{}^6{}_{}{}^{}\mathrm{Li}, 3n){}_{}{}^{A+3\mathrm{}}{}_{}{}^{}\mathrm{I}$ reactions to study the collective properties of the odd-mass I isotopes. A similar study of ${}_{}{}^{123,125,127}{}_{}{}^{}\mathrm{I}$ is reported in the preceding paper. Two collective features have been observed: $\Delta J=1\mathrm{}$ bands built on low-lying ${\frac{9}{2}}^{+}$ proton-hole states and $\Delta J=2\mathrm{}$ bands built on ${\frac{11}{2}}^{-}$, ${\frac{7}{2}}^{+}$ and ${\frac{5}{2}}^{+}$ quasiproton states. The $\Delta J=2\mathrm{}$ energy spacings for the ${\frac{11}{2}}^{-}$ bands decrease significantly relative to those for the ground-state bands of the Te core nuclei as $A$ decreases, but not for the ${\frac{7}{2}}^{+}$ and ${\frac{5}{2}}^{+}$ $\Delta J=2\mathrm{}$ bands. This unexpected decrease can be explained in a generalized seniority scheme. The systematic properties of the $\Delta J=2\mathrm{}$ bands for all of the odd-mass I isotopes are summarized. These collective properties are examined in terms of both the microscopic and phenomenological approaches. Pulsed-beam-$\gamma$ measurements yielded mean lifetimes of $\tau =17.5\mathrm{}\pm 1.0, 41.5\pm 1.5, 13.5\pm 0.5$ ns for the ${\frac{9}{2}}^{+}$ proton-hole states in ${}_{}{}^{117,119,121}{}_{}{}^{}\mathrm{I}$, respectively. These values imply hindrances of ∼ ${10}^4$ relative to $M1\mathrm{}$ Weisskopf estimates for the transitions to the ${\frac{7}{2}}^{+}$ quasiproton states. A spin rotation measurement yielded a $g$ factor for the ${\frac{9}{2}}^{+}$ isomer in ${}_{}{}^{119}{}_{}{}^{}\mathrm{I}$ of $g=1.21\mathrm{}\pm 0.08$. Another isomer with a mean life of $\tau =13\mathrm{}\pm 2$ μs was observed at 2377 keV in ${}_{}{}^{121}{}_{}{}^{}\mathrm{I}$.

NUCLEAR REACTIONS ${}_{}{}^{114-118}{}_{}{}^{}\mathrm{Sn}({}_{}{}^6{}_{}{}^{}\mathrm{Li}, 3n){}_{}{}^{117-121}{}_{}{}^{}\mathrm{I}$; measured $\gamma -\gamma -t$ coincidences, $\gamma (E, \theta , t)$, spin rotation in $B=13.4\mathrm{}$ kG; deduced level schemes in odd-mass ${}_{}{}^{117-121}{}_{}{}^{}\mathrm{I}$, $\gamma$ multipolarities, $J^{\pi }$, $T_{\frac{1}{2}}$, $g$ factor. Enriched targets, Ge(Li) detectors.

Gamma-ray multiplicity (first and second moments) has been measured in the 60 MeV proton-induced fission of ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$. From this work we have evidence that shell effects play an effective role at the scission point, even at an excitation energy of 65 MeV. Collective modes seem to be more easily excited when the nascent fragments are far from spherical shapes. The $\gamma$-multiplicity moments seem to depend weakly on excitation energy of the fissioning nucleus and do not really reflect the angular momentum of the entrance channel. The good agreement of our results with the Moretto-Schmitt model highly supports the role played by collective modes (bending) in the heavy ion induced fission and deep inelastic collisions which are presently the field of many recent experimental and theoretical investigations.

NUCLEAR REACTIONS $p$+${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$; $E_p=60\mathrm{}$ MeV; measured fission fragment mass distribution $\frac{\mathrm{dN}}{\mathrm{dM}}$; measured $\gamma$-ray multiplicity first and second moments $〈M_{\gamma }〉$ and ${\sigma }_{\gamma }$ functions of fragment mass ratios $\alpha$ and $E_{\mathrm{TKE}}$;; measured average $\gamma$-ray energy $〈E_{\gamma }〉$ ($\alpha$); measured in-plane, out-of-plane ${〈M_{\gamma }〉}_{\alpha }\left(\theta \right)$; comparison to s.f. and HI reaction mechanisms and to Moretto-Schmitt model; deduced effects of collective rotational modes (bending) on fragment spins.

A few variations of the two potential formalism will be presented. Firstly, a new derivation of the standard two potential approach is given. Secondly, the proof of the previously proposed coupled channel approach is upgraded, and thirdly, a new distorted wave expression for the two potential problem is proposed. The new formalism is applied to the Coulomb-nuclear interference phenomena, paying due attention to the singularities of the Coulomb potential matrix element and scattering amplitude, and the finite size effect of interacting particles. To demonstrate the applicability of the new formalism, $\pi$-${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ elastic scattering differential cross sections are calculated.

NUCLEAR REACTIONS Two potential approach, new distorted wave integral equation, Coulomb-nuclear interference, calculated $\sigma \left(\theta \right)$ for ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(\pi , \pi )$.

Expressions are derived for the partial wave expansion coefficients of the scattering matrix elements corresponding to one-particle-exchange Feynman diagrams which are modified by form factors or by Reggeization. A few examples are presented, including the application to nucleon-nucleon scattering in the cloudy bag model. A value of the bag radius $R\simeq 0.8$ fm seems to be consistent with the phase-shift analysis in selected partial waves.

NUCLEAR REACTIONS Modified one particle exchange diagrams applied to $N-N$ scattering.

The new measurements of polarization $P$ and spin rotation function $Q$ in 500 MeV $p$-${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ elastic scattering require geometric differences among the various parts of the $p$-nucleus interaction. We present a general analytic formalism which defines these differences and shows how the new experiments can be interpreted as interferometric determinations of them.

NUCLEAR REACTIONS Closed form spin-dependent $p$-nucleus scattering amplitudes. Data-to-data relations for polarization and spin rotation.

We present a parametrization of the $\pi -N$ interaction in the $P_{11}$ channel in which the amplitude is the sum of a pole part and a non-pole part ($t=t_{\mathrm{pole}}+t_{\mathrm{np}}$) and satisfies two-body unitarity. Here $t_{\mathrm{pole}}$ has both the nucleon propagator and the $\pi \mathrm{NN}$ vertex dressed. The final amplitude fits the scattering length and low energy $\pi -N$ phase shifts ($T_{\pi }^{\mathrm{lab}}<300\mathrm{}$ MeV). We study the effect of a resonance in $t_{\mathrm{np}}$ on the phase shifts, $\pi \mathrm{NN}$ coupling constant, and the off-shell behavior of the amplitude.

NUCLEAR REACTIONS $\pi N$ scattering in $P_{11}$ channel, renormalization, resonance effect.