Excitation functions for the reaction¹⁸¹Ta (α,xn)^185−xRe,^107,109Ag (α, ypxn) and⁵⁹Co (α, ypxn) were obtained from measurements of residual activity of stacked foils from threshold to 60 MeV. The excitation functions for the production of¹⁸¹Re,¹⁸²Re,¹⁸³Re,¹⁸⁴Re,¹⁰⁵Ag,¹¹¹In,⁵⁴Mn,⁵⁶Co,⁵⁸Co, and⁶⁰Co, are being presented. The experimental data are compared with calculations considering equilibrium as well as pre-equilibrium reactions according to the hybrid model of Blann. High energy part of the excitation functions is dominated by the pre-equilibrium reaction mechanism. Calculations were done using a priori calculational method of Overlaid Alice Code of Blann. Most of the excitation functions in the energy range mentioned above could be very well fitted with the hybrid model calculation for exciton numbern=4 withn_p=2 andn_n=2. The overall agreement with theory is good. Certain discrepancies, however, indicate the necessity to revise the hybrid model with respect to emission of complex particles.

Excitation functions for the reactions¹²¹Sb(α, xn)^125−xI,¹²³Sb(α, xn)^127−xI and¹²¹Sb(α, p3n)¹²¹Te were obtained from the measurements of the residual activity of stacked foils of antimony trioxide evaporated on Al backings from threshold to 60 MeV. The excitation functions for the production of¹²¹I,¹²³I,¹²⁴I,¹²⁶I and¹²¹Te are presented. The experimental data are compared with calculations considering equilibrium as well as pre-equilibrium reaction mechanism according to the hybrid model of Blann. The high energy part of the excitation functions are dominated by the pre-equilibrium reaction mechanism. Calculations were done using a priori calculational method of Overlaid Alice Code of Blann. Most of the excitation functions in the energy range mentioned above could very well be fitted with the hybrid model calculation for exciton numbern=4 withn_n=2 andn_p=2. The overall agreement with the theory is good. Certain discrepancies for example¹²¹Sb(α, p3n)¹²¹Te excitation function, indicate that the production mechanism is different from the one presumed for the calculation.

Excitation function and mean projected recoil ranges of nuclei produced in theα-particle induced reactions on F, Al, V, Co and Re targets were measured by conventional thick target thick recoil catcher technique for bombarding energiesE_α≤65 MeV. The measured cross-sections are compared with calculations considering equilibrium as well as pre-equilibrium reaction mechanism according to the hybrid and geometry dependent hybrid (GDH) model of Blann using the code Alice/85/300. High energy part of the excitation functions are dominated by pre-equilibrium reaction mechanism whereas the low energy parts are dominated by evaporation with its characteristic peak. In this paper emphasis will be placed on the GDH model, for it provides a potentially better description of the physical process i.e., a higher probability of peripheral collisions to undergo precompound decay than for central collisions. Geometry dependent model with initial exciton numbern₀=4 (n_n=2,n_p=2,n_k=0) gives better fits compared to hybrid model with same initial exciton configuration andmfp parameterk=1.0 forα-induced reactions on F, V, Co and Re. Whereas forα-induced reaction on Al comparatively large initial exciton configurations (8/4/4/0) or (10/5/5/0) were required to fit the excitation functions reasonably well. Recoil ranges were converted into recoil momentum and vice versa using Lindhard, Scharff and Schiott (LSS) and Blaugrund theories. These theories were also used to calculate projected recoil ranges for full momentum transfer pertaining to fusion reactions. The momentum transfer information was used to get clues about some aspect of the interaction from the trends and magnitudes of the observed ranges.

Excitation function and mean projected recoil ranges of nuclei produced in the¹²C-induced reactions on⁵¹V target were measured by conventional stacked foil and thick-target thick-recoil-catcher technique for bombarding energiesE ≤ 84 MeV for¹²C ion beam. The measured recoil ranges are converted to momentum transfer. Information on momentum transfer was used to get clues about some aspects of the interaction such as complete fusion which corresponds to full momentum transfer and incomplete fusion reaction mechanism. The measured excitation functions are compared with the calculation based on the statistical model which describes only equilibrium decay of the compound nucleus using the Cascade code and the geometry dependent hybrid model which describes equilibrium as well as pre-equilibrium decay of the compound nucleus using the Alice/91 code. The measured excitation functions and average ranges of the radioisotope products of the reactions¹²C on⁵¹V indicate that the three separate reaction mechanisms could be attributable to complete fusion of¹²C, incomplete fusion of⁸Be and incomplete fusion of⁴He respectively with the target. The⁸Be and⁴He are the break-up component of¹²C into⁸Be +⁴He. The predictions of the codes, especially the Cascade, generally agree with the measured cross-sections which could be attributed to complete fusion of¹²C with the target⁵¹V.

Excitation functions and a few isomeric cross-section ratios for production of (1)¹⁹²Au,¹⁹³Au,¹⁹⁴Au,¹⁹⁵Au and¹⁹²Ir nuclides inα-induced reactions on^191,193Ir, (2)¹⁹⁷Tl,^197mHg,^198m,gTl,¹⁹⁹Tl and²⁰⁰Tl nuclides inα-induced reaction in¹⁹⁷Au and (3)¹⁸³Re and^184m,gRe nuclides inα-induced reaction in¹⁸¹Ta and¹⁸⁵Re are obtained from the measurements of the residual activities by the conventional stacked-foils technique from threshold to 50MeV. The excitation function and isomeric cross-section ratios for nuclear reaction¹⁸¹Ta(α,n)^184m,gRe are compared with the theoretical calculation using the code Stapre which is based on exciton model for pre-equilibrium phase and Hauser-Feshbach formalism taking angular momentum and parity into account for the equilibrium phase of the nuclear reaction. All other experimental excitation functions are compared with the calculations considering equilibrium as well as pre-equilibrium reaction mechanism according to the geometry dependent hybrid (GDH) model and hybrid model of Blann using the code Alice/91. The high energy part of the excitation functions are dominated by pre-equilibrium reaction mechanism whereas the low energy parts are dominated by equilibrium evaporation with its characteristic peak. The GDH model provides a potentially better description of the physical process (i.e., a higher probability for peripheral collisions to undergo precompound decay than for central collisions) compared to hybrid model. However in the energy range of present measurement most of the excitation functions are fitted reasonably well by both GDH model and hybrid model with initial exciton numberN₀=4(N_n=2,N_p=2,N_h=0). Barring a few reactions we have found the overall agreement between theory and experiment is reasonably good taking the limitations of the theory into account.