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Intermediate-mass fragments formed in reactions of $^{3}\mathrm{He}$ ions with $^{\mathrm{nat}}\mathrm{Ag}$ and $^{197}\mathrm{Au}$ targets have been studied at five energies between 0.48 and 3.6 GeV. Inclusive measurements show that as the bombarding energy increases, there is a strong enhancement in fragment cross sections and a trend toward isotropic angular distributions. Between 0.90 and 1.8 GeV, a change in the emission mechanism is suggested by (1) kinetic energy spectra with high-energy tails that become distinctly flatter, (2) a broadening of the spectral Coulomb peaks toward lower energies, and (3) charge distributions that become constant, exhibiting a power-law exponent \ensuremath{\tau}\ensuremath{\approxeq}2.0. Exclusive studies of the $^{3}\mathrm{He}$${+}^{\mathrm{nat}}$Ag system at 0.90 and 3.6 GeV detected multifragment events with multiplicities up to four. The probability for high-multiplicity events increases about 40-fold between 0.90 and 3.6 GeV. At both energies, the kinetic energy spectra depend on multiplicity, especially when triggering on backward-emitted fragments. For multiplicity three events, a rapidity analysis of the data at 3.6 GeV is consistent with a single, relatively low source velocity, ${\mathit{v}}_{\mathit{S}}$\ensuremath{\approxeq}0.4 cm/ns. The data are compared with predictions of a coplanarity-sphericity calculation, the sequential statistical decay code GEMINI, and a hybrid intranuclear cascade/percolation model.

Analyzing powers and isotope ratios have been measured for ejectiles with Z\ensuremath{\le}7 emitted at forward angles in the 200-MeV p\ensuremath{\rightarrow}${+}^{\mathrm{nat}}$Ag reaction. The observed analyzing powers are consistent with zero, and thus do not provide evidence for a significant contribution from cluster knockout, or similar direct formation mechanisms. Fragment kinetic-energy spectra above the Coulomb peak are compared with a coalescence calculation. The isotopic composition of the elemental kinetic-energy spectra is found to favor N/Z\ensuremath{\ge}1 nuclei for fragment energies near the exit-channel Coulomb energy, whereas species with N/Z\ensuremath{\le}1 are more abundant in the high-energy spectral tails. This behavior is consistent with the predictions of an accreting source calculation.

Two-proton correlation functions, measured at small relative momenta in the $^{3}\mathrm{He}$+Ag reaction at 200 MeV, increase monotonically with the kinetic energy of the detected particles. Very strong correlations are observed for intermediate energy protons. These correlations scale with the weaker correlation functions measured for heavier projectiles, and can be reproduced by the Boltzmann-Uehling-Uhlenbeck equation. Even stronger correlations measured for beam velocity protons, however, may be remnants of the initial state wave functions of the $^{3}\mathrm{He}$ projectiles.

Two-proton correlation functions have been measured at {theta}{sub lab}{approx}25{degree} for the forward kinematics'' reactions {sup 14}N+{sup 27}Al, {sup 14}N+{sup 197}Au at {ital E}/{ital A}=75 MeV, for the inverse kinematics'' reaction {sup 129}Xe+{sup 27}Al at {ital E}/{ital A}=31 MeV, and for the nearly symmetric reaction {sup 129}Xe+{sup 122}Sn at {ital E}/{ital A}=31 MeV. For the reactions at 75 MeV per nucleon, the correlation functions exhibit pronounced maxima at relative proton momenta, {ital q}{approx}20 MeV/{ital c}, and minima at {ital q}{approx}0 MeV/{ital c}. These correlations indicate emission from fast, nonequilibrium processes. They are analyzed in terms of standard Gaussian source parametrizations and compared to microscopic simulations performed with the Boltzmann-Uehling-Uhlenbeck equation. For the reactions at 31 MeV per nucleon, the two-proton correlation functions do not exhibit maxima at {ital q}{approx}20 MeV/{ital c}, but only minima at {ital q}{approx}0 MeV/{ital c}. These correlations indicate emission on a slower time scale. They can be reproduced by calculations based on the Weisskopf formula for evaporative emission from fully equilibrated compound nuclei. For all reactions, the measured longitudinal and transverse correlation functions are very similar, in agreement with theoretical predictions.

Two-proton correlation functions measured for the {sup 14}N+{sup 27}Al reaction at {ital E}/{ital A}=75 MeV are compared to correlation functions predicted for collision geometries obtained from numerical solutions of the Boltzmann-Uehling-Uhlenbeck (BUU) equation. The calculations are in rather good agreement with the experimental correlation function, indicating that the BUU equation gives a reasonable description of the space-time evolution of the reaction.

The excitation-energy distribution of projectilelike fragments formed in the {ital E}/{ital A}=8.5 MeV {sup 74}Ge+{sup 165}Ho reaction has been obtained by applying a statistical evaporation calculation to the difference between primary fragment mass yields derived from kinematic coincidence measurements and directly measured yields. A gradual transition from approximate equipartition of excitation energy for small energy losses to a division that favors the targetlike fragment for highly damped events is observed, in agreement with previous measurements. For a given energy loss, heat partition is found to correlate with the direction of net nucleon transfer. The variances of the excitation-energy distributions are shown to increase monotonically as a function of energy loss. The average data are compared with predictions of the nucleon exchange transport model. The results suggest that energy-loss mechanisms in addition to nucleon exchange may be important in the early stages of the collision.

Mass and charge distributions have been measured for damped projectile-like fragments in the reaction {sup 74}Ge+{sup 165}Ho at 8.5 MeV per nucleon bombarding energy. Coincidences were measured between {ital Z}- and {ital A}-identified projectile-like fragments and angle-correlated heavy reaction partners in order to derive the primary mass distribution for projectile-like fragments. Centroids and variances of the primary and post-evaporative {ital Z}, {ital N}, and {ital A} distributions are presented. The evolution of the primary {ital N} and {ital Z} distributions as a function of energy loss is found to deviate from predictions of the nucleon exchange transport model.

Multi-breakup processes for the {sup 124}Sn+{sup 64}Ni system at 35 MeV/nucleon have been studied with the forward part of the CHIMERA detector. An extensive comparison between experimental data corresponding to almost complete ternary events and constrained molecular dynamics (CoMD-II) calculations suggests different characteristic times in the selected processes. This is in agreement with previous studies of the same reaction already published concerning the prompt intermediate-mass-fragment emission. Stimulated by CoMD-II calculations, we investigate the existence of more complex dynamical multi-breakup processes occurring on the same time scale. A detailed study of the rotational dynamics leading to slower dynamical fission processes is also presented.

Chatterjee [ital et] [ital al]. [Phys. Rev. C 44, R2249 (1991)] report that the sharing of dissipated energy in the [sup 58]Ni + [sup 208]Pb reaction at [ital E]/[ital A]=6.5 MeV is not influenced appreciably by the direction and magnitude of net charge (and mass) transfer. We point out that neither this conclusion nor one arguing for a correlation between mass flow and excitation energy division is supported by the data and analysis presented in their communication.

Inclusive and coincidence measurements have been performed to study symmetric fragmentation of $^{44}\mathrm{Ti}$ binary decay from the $^{32}\mathrm{C}$ reaction at 280 MeV incident energy. Element distributions after binary decay were measured. Angular distributions and fragment correlations are presented. Total c.m. kinetic energy for the symmetric products is extracted from our data and from Monte-Carlo model calculations including Q-value fluctuations. This result was compared to liquid drop model calculations and standard fission systematics. Comparison between the experimental value of the total kinetic energy and the rotating liquid-drop model predictions locates the angular momentum window for symmetric splitting of $^{44}\mathrm{Ti}$ between 33\ensuremath{\Elzxh} and 38\ensuremath{\Elzxh}. It also showed that 50% of the corresponding rotational energy contributes to the total kinetic energy values. The dominant reaction mechanism was found to be symmetric splitting followed by evaporation.

Inclusive and coincidence measurements have been performed to study symmetric products from the reactions 74--186 MeV /sup 12/C+ /sup 40/Ca, 141 MeV /sup 9/Be+ /sup 40/Ca, and 153 MeV /sup 6/Li+ /sup 40/Ca. The binary decay of the composite system has been verified. Energy spectra, angular distributions, and fragment correlations are presented. The total kinetic energies for the symmetric products from these very light composite systems are compared to liquid drop model calculations and fission systematics.

Nuclide distributions have been measured for damped collision products formed in the reaction of E/A=8.5 MeV $^{58}\mathrm{Ni}$ and $^{64}\mathrm{Ni}$ ions with $^{238}\mathrm{U}$. The data demonstrate that in these very asymmetric systems the evolution of the nucleon-exchange process as a function of energy loss depends strongly on the N/Z value of the projectile and the corresponding gradient in the potential-energy surface. Comparison of the data with transport model calculations shows qualitative agreement with the N and Z centroids, variances, and correlation coefficients. However, absolute discrepancies exist which suggest the need for improvement in the model.