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Gamma ray spectra in the energy range of ∼4–25 MeV were measured in the reaction 28 Si + 124 Sn at E ( 28 Si) ∼ 150 MeV in coincidence with low energy γ -multiplicities. The spectra were analysed using a simulated Monte Carlo CASCADE code. The centroid energy and width of the giant dipole resonance were extracted for various multiplicity windows. The average angular momentum and temperature of the final states populated after the giant dipole photon emission range from ∼25 ℏ and 1.5 MeV to ∼56 ℏ and 1.3 MeV, respectively. The extracted widths are almost constant for the lower multiplicity windows and show an increase of ∼1.4 MeV at the highest window. The nuclei are expected to be near the liquid drop regime and the experimental results are not inconsistent with the liquid drop behaviour.

Gamma multiplicity gated proton spectra have been measured in the 12C + 93Nb reaction at E ( C 12 ) = 40 MeV at backward angles. The shape of the spectrum shows a drastic change with the increase in multiplicity acquiring a broad structure at proton energies beyond ∼ 15 MeV corroborating our earlier measurements at E ( C 12 ) = 42.5 MeV . Measurements made in coincidence with residue γ rays, detected in an array of eight HPGe clover detectors, confirm these observations. An excitation energy and angular momentum-dependent enhancement of the nuclear level density or a massive cluster transfer of 11B to the 93Nb can explain the data.

Proton and alpha spectra in the energy range E p c.m. ∼6 –24 MeV and E α c.m. ∼12 –40 MeV, respectively, have been measured in the reaction 28 Si + 58 Ni at E lab ( 28 Si )=100 and 125 MeV. The spectra at various laboratory angles from 100° to 160° were corrected for angular distribution effects to obtain the angle-integrated spectra. An asymptotic (liquid drop) level density parameter of a =A/7.5 describes the proton and alpha spectra at both the beam energies. No lowering of emission barrier is needed to explain the alpha spectra although the spin dependence of level density has to be tuned. The derived value of a is somewhat larger than that for other near-stable nuclei and possibly arises due to the excitation energy dependent collective enhancement of the nuclear level density.

High-energy proton spectra in the energy range E p c.m. ∼8.5–25 MeV are measured in the reaction 12 C+ 93 Nb at E lab ( 12 C)=42.5 MeV and at laboratory angles of 130°, 145° and 160°. The spectra, recorded in coincidence with a gamma ray multiplicity detector array, show a broad structure which becomes more prominent at higher multiplicity. The centroid of the structure shifts with multiplicity. These features could arise from an unusual spin and excitation energy dependence of the nuclear level density in Pd and Ag nuclei with mass around A =104. However, a non-statistical process, viz. , the massive cluster transfer, cannot be ruled out.