Search

The experimental differential cross section of the 12C + 12C elastic scattering over a wide laboratory energy scale 25 ⩽ E lab ⩽ 360 MeV are analyzed within the framework of the optical model (OM) using non-monotonic (NM) nucleus–nucleus potential. The real parts of the NM potentials are derived from the energy density functional (EDF) formalism with the sudden approximation embodying the Pauli exclusion principle and the imaginary parts are taken as phenomenology. The diffractive and the refractive scattering with Airy structures in the whole angular region of the 12C + 12C elastic scattering in the above mentioned energy range are found profoundly successful in OM with the NM nucleus–nucleus potentials in five of different potential families. All the families at lower energies converge at 240 MeV to the unique potential family starting with the EDF potential. This, in conjunction with our recent findings for the 16O + 16O system in Islam et al (2021 J. Phys. G 48 075109), not only verifies the Goldberg criterion for elimination of discrete potential ambiguities for NM potentials, but also establishes that this leads uniquely to the EDF family. The 90° excitation function is also successfully reproduced with extension using NM potentials. The near- and far-side (N/F) decomposition of total elastic scattering amplitude has also been studied using our NM potentials.

The differential, integrated elastic, momentum transfer, viscosity and total cross-sections along with Sherman function for the elastic scattering of electrons and positrons by sodium atoms...

The Sternglass theory [Sternglass, Phys. Rev. 108, (1957) 1] for fast-ion-induced secondary-electron emission, which is proportional to the stopping powers, from metals has been modified to calculate the electron impact secondary electron yield from both elemental and compound targets with atomic number Z = 4–92 for incident energy range 5 ≤ E i ≤ 10 5 eV . This modification includes the use of a realistic stopping power expression that involves calculations of the effective atomic electron number, effective mean excitation energies and realistic electron density distribution of the target atoms along with the effective charge of incident electron. Throughout the studied energy range, the predictions of our proposed theory are in reasonable agreement with the experimental data for Be to U elemental and six important compound targets.

A simple modification of the Vaisburd and Evdokimov model (VE) [Russ. Phys. J. 46 , 1160 (2003)], with a acronym MVE, embodying the relativistic effects is proposed and employed to evaluate the K -shell ionization cross sections of atomic targets with atomic numbers 6 ≤ Z ≤ 92 for incident energies E Threshold ≤ E ≤ 10 GeV. For a meaningful comparison we also revisited our earlier MUIBED model [Int. J. Q. Chemistry, 108 , 1023 (2008)] to obtain the K -shell ionization cross sections for 24 atomic targets and above mention energy range. It is found that our new results from the MVE model agrees quite well not only with available experimental data but also with other theoretical values.

‘Goldberg criterion’ [Goldberg and Smith, Phys. Rev. Lett. 29 (1972) 500] tells that at sufficiently high energies, where pronounced refractive scattering with nuclear rainbow oscillations are followed by an ‘exponential-type falloff’ in the angular distribution, discrete ambiguities are eliminated for the deep monotonic potential. The criterion is also confirmed in the work of Bartnitzky et al. [Phys. Lett. B 365 (1996) 23] on the 16O+16O elastic scattering in the energy range of 250 - 704 MeV. However, their finding ‘using model-independent potentials’ suggests that heavy-ion elastic scattering data unambiguously favour deep potentials. The Goldberg criterion is examined in our work for non-monotonic shallow potentials using the 16O+16O elastic scattering at energy region up to 350 MeV.

A novel method for the determination of the yet not well-known quantity of nuclear incompressibility, K is presented. Non-monotonic (NM) nucleus-nucleus potentials from the energy-density functional (EDF) theory including the Pauli principle have been considered for K in the range 188-266 MeV. The experimental cross sections of 16O+16O elastic scattering over the 31-350 MeV incident energies have been analyzed in the optical model using the NM potentials. Sensitivity of K on the elastic scattering data is studied and its value for infinite cold nuclear matter deduced to be 222 ± 5 MeV

This work illustrates, for the first time, the analysis of tensor analyzing powers (T 20, T 21, T 22) along with the differential cross-section (CS) and the vector analyzing power iT 11 for the 6Li+12C elastic scattering at 30 and 50 MeVwithin the framework of an optical model (OM) using microscopic shallow non-monotonic (NM) potentials. The NM potential is generated from the energy density functional formalism (EDF) [Brueckner et al., Phys. Rev., 168 (1968) 1184] using a realistic two-nucleon interaction incorporating Pauli Exclusion principle. The shallow NM potential can describe the experimental angular distributions of CS and analyzing powers of the elastic scattering data. The OM analysis of the data at this energy does not indicate their sensitivity on the nuclear matter incompressibility K.

This paper reports on the differential, integral, momentum transfer and viscosity cross sections along with spin polarisation for elastically scattered electrons and positrons from iron atoms in th...

This work reports, for the first time, the analysis of tensor analyzing powers (T 20, T 21, T 22) along with the differential cross-section (CS) and the vector analyzing power iT 11 for the 6Li + 12C elastic scattering at 30 and 50 MeV within the framework of an optical model (OM) using microscopic shallow non-monotonic (NM) potentials. The NM potential is generated from the energy density functional formalism (EDF) (Brueckner et al (1968) Phys. Rev. 168 1184) using a realistic two-nucleon interaction incorporating the Pauli exclusion principle. The shallow NM potential can describe the experimental angular distributions of CS and analyzing powers of the elastic scattering data. The OM analysis of the data at 30 and 50 MeV does not indicate their sensitivity on the nuclear matter incompressibility K.

Stopping cross sections (SCS) for protons, alphas and Li ions are calculated with a modified form of our earlier work by incorporating a different electron density distribution of target materials; this involves four parameters – two projectile dependent and the rest two remain fixed. The prosed model has been tested for three stripped ion (H+, He2 + and Li3 +) projectiles and found that it describes quite satisfactorily the experimental SCS data from low energies with projectile velocities nearing v = Z1v0 (with Z1 as the atomic number and v0 the Bohr velocity) up to 100.0 MeV over a wide range of stopping media with atomic numbers Z2 =3–100.

Calculations of electron-impact ionization cross sections (EIICS) for L -subshell of neutral atoms with atomic number Z = 14–92 and also for M -subshell targets, having atomic number Z = 35–92 for incident energies E threshold ≤ E ≤ 10 6 keV, have been reported. This review comprises the results of our two easy-to-use models, capable of reproducing very closely the experimental EIICS data. We also show systematically how these models can be implemented easily to generate accurate data as demanded by various model applications. The choice of the range of atomic number Z for both L - and M -subshell targets was made possible by the wealth of the EIICS data in literature either from experiments or from rigorous quantal calculations. The detailed findings due to our XMCN and XMUIBED models are compared with the experimental and other theoretical results. Present results describe the experimental data quite well for the L - and M -subshell for various atomic targets over a wider range of projectile energy.

The differential, total, and momentum transfer cross sections along with the minima in the differential cross sections (DCSs) and the Sherman function S(θ) for the elastic scattering of electrons by calcium atoms have been calculated. These calculations are done within the framework of complex electron–atom optical potential and relativistic dynamics, in the energy range 1–2000 eV. The results obtained are in good agreement with the available experimental data and are better than the previous calculations in overall assessment. In the DCSs, the energies and angular positions of five critical minima have been confirmed. In the vicinity of these critical minima, nine maximum polarization points have been found within the range −0.90 ≤ S(θ) ≤ +0.73. Near the critical minima, a strong energy dependence of maximum polarization points is found.

The model of Cengiz (2002) [Approximate inelastic scattering cross sections of electrons. Rad. Phys. Chem. 65, 33–44] has been modified by incorporating both the ionic and relativistic corrections due to Uddin et al. (2006) [Modified Kolbensvedt model for the electron impact K-shell ionization cross-sections of atoms and ions. Eur. Phys. J. D 37, 361–369.] to investigate the electron impact s-orbital ionization in the K- and L-shells. With a single set of species independent parameters our evaluated inner shell ionization cross section of atomic targets from H to U over incident energies up to 2 GeV and of H- to Be-isoelectronic series reproduce the experimental findings nicely.

The elastic, differential and integrated, and total cross sections for the scattering of electrons and positrons by magnesium atom have been calculated. These calculations are done within the framework of complex electron/positron-atom optical potential and relativistic Dirac partial wave analysis at the impact energies 0.1–1000 eV for both the projectiles. The present results are compared with available experimental data and some other theoretical calculations.

A simple modification of the revised Deutsch–Mark model (RDM) [Deutsch et al., Int J Mass Spectrom 2004, 233, 13] incorporating both the ionic and relativistic corrections is proposed to investigate the K-shell ionization of 30 atomic targets with atomic numbers Z = 1–92 for incident energies up to 2 GeV. We also revisit our earlier models: modified Bell (MBELL) (Haque et al., Phys Rev A 2006, 73, 012708) and modified Kolbenstvedt (MKLV) (Uddin et al., Eur Phys J D 2006, 37, 361), for the K-shell ionization cross sections at these ultra-relativistic energies. The results from the modified version of RDM (MRDM), MBELL, and MKLV models agree well with the available experimental data and quantum mechanical calculations. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009

A new semiempirical model comprising few important features of the DM model of Deutsch et al. (Int J Mass Spectrom 1998, 177, 47) and the widely used empirical model of Bell et al. (J Phys Chem Ref Data 1983, 12, 891) has been proposed. The proposed model has been examined to evaluate the electron impact K-shell ionization cross sections of 30 atomic targets ranging from H to U (Z = 1–92) and found to describe with considerable success the experimental results over a wide range of incident energies up to 2 GeV using a single set of species independent parameters. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2009

We propose an extension of the modified simplified-improved-binary-encounter dipole (MRIBED) model (Uddin et al., Phys Rev A 2005, 72, 032715), incorporating both the ionic and relativistic corrections, to investigate the K-shell ionization of atomic targets with atomic numbers Z = 1 − 92 for incident energies up to 2 GeV. We also revisit our earlier models, MBELL (Haque et al. Phys Rev A 2006, 73, 012708) and MKLV (Uddin et al. Eur Phys J D 2006, 37, 361), for the K-shell ionization at these ultra-relativistic energies. The results from our extended version of MRIBED, MBELL, and MKLV models agree well with the experimental findings. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008

The electron impact K-shell ionization (EIKSI) cross sections on 18 atomic targets, with the atomic numbers 2 Z 92, are calculated using a modified version of the binary encounter approximation (BEA) model. The modified BEA (MBEA), which incorporates both ionic and relativistic corrections and is simpler in application than other existing models, is found to be immensely successful in describing the EIKSI data up to the incident energy of 1 GeV. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem 108: 1326 -1333, 2008

Calculations of electron impact ionization cross sections (EIICS) for H to Sc (with atomic number Z =1–21) and their corresponding isoelectronic series over incident energies up to 106 keV have been reviewed. This work reports the results of calculations using our various easy-to-use models reproducing closely the experimental EIICS data. We also report how these models can easily be implemented to generate accurate data as demanded by various model calculations. The selection of the range of atomic number Z for different isoelectronic series was made possible by the wealth of the EIICS data either from experiments or from rigorous quantum calculations. We have furnished the detailed description of our various models with comparison of the outcomes of these models with experimental and other theoretical results. Our models describe the experimental results with reasonable success for various atomic and ionic targets belonging to the H to Sc isoelectronic series over a wide range of atomic number in each series.

A simple empirical formula is proposed for the rapid calculation of electron impact total ionization cross sections both for the open- and closed-shell neutral atoms considered in the range 1≤ Z≤92 and the incident electron energies from threshold to about 104 eV. The results of the present analysis are compared with the available experimental and theoretical data. The proposed model provides a fast method for calculating fairly accurate electron impact total ionization cross sections of atoms. This model may be a prudent choice, for the practitioners in the field of applied sciences e.g. in plasma modeling, due to its simple inherent structure.

The real parts of the alpha-alpha and alpha-nucleus potential, particularly for40,44,48Ca and58Ni targets are determined from a realistic two-nucleon potential using an energy-density functional approach and are found to be non-monotonic with a short range repulsion in their functional forms that are similar to those needed in accounting for elastic scattering data. The deduced alpha-alpha potential has no bound states and the calculated decay width of8Be of about 6.4 eV at about 200 keV energy is in agreement with the measurement.

The recently modified Kolbenstvedt (MKLV) model [Eur. Phys. J. D 37, 361 (2006)], developed for electron impact ionization (EII) of the K-shell atomic targets, has been extended to generalize its two parameters in terms of the electronic orbitals nl. The generalized MKLV (GKLV) with two sets of the species independent parameters for the same nl, one set for the ionization of inner orbits and another for the outermost orbit, is found profoundly successful in accounting for the EII cross section data of the K, L and M-shell neutral atoms with atomic numbers Z = 1-92 for the incident energies up to 1000 MeV in a consistent manner.

The modified BELL (MBELL) formula (Haque et al 2006 Phys. Rev. A 73 012708) has been applied to the M-shell ionization of neutral and ionic atoms to deduce the `generalized' parameters of the 3s, 3p and 3d orbits. A single set of parameters for each of these orbits and that previously determined for each of 1s, 2s and 2p orbits can reproduce satisfactorily the features of the total electron impact ionization cross-sections (EIICS) of 21 M-shell targets in the Na, Mg, Al, Si, P, S, Cl, Ar and Ca isoelectronic sequences. The generalized parameters are also found to provide an excellent account of the M-shell EIICS data of Pb, Bi and U atoms at relativistic energies in the range from 20 to 250 MeV.

Experimental differential cross sections for elastic scattering of two α particles have been fitted with an l -independent non-monotonic real potential up to 34.2 MeV (lab) and a complex potential with non-monotonic real part from 35.1 to 47.3 MeV (lab). The calculated phase shifts, in general, agree with those derived from the phase shift analyses of the experimental cross sections. In particular, the s- and d-wave phase shifts tend to zero in the limit of zero energy implying the absence of any bound state. Thus, 8 Be is unbound in the potential and the calculated decay width of about 6 eV agrees with the observed one. This potential has its roots in the energy-density functional (EDF) theory with the sudden approximation. In fact, the calculated angular distributions using the derived EDF potential are in reasonable agreement with the experimental data at some energies up to 15.2 MeV (lab). Modifying the Buck, Friedrich and Wheatley (BFW) potential by adding a small repulsive core leads to about the same quality of fits. The modified BFW potential, however, binds 8 Be in Pauli forbidden states, and s- and d-wave phase shifts in it tend to 2 π and π , respectively, in the limit of zero energy.

The parameters of our recent modification of BELI formula (MBELL) [A.K.F. Haque, M.A. Uddin, A.K. Basak, K.R. Karim, B.C. Saha, Phys. Rev. A 73 (2006) 012708] are generalized in terms of the orbital quantum numbers nl to evaluate the electron impact ionization (EII) cross sections of a wide range of isoelectronic targets (H to Ne series) and incident energies. For both the open and closed p-shell targets, the present MBELL results with a single parameter set, agree nicely with the experimental cross sections. The relativistic effect of ionization in the 2p subshell of U 82+ for incident energies up to 250 MeV is well accounted for by the prescribed parameters of the model.

The electron impact ionization cross-sections of mono- and di-positive ionic targets are calculated using a second version of the modified binary-encounter-dipole (MBED) model, previously reported [M A Uddinet al, J. Phys. B37, 1909 (2004)]. The present version differs from the previous one in the scale factor of the Burgess denominator and is applicable to targets with chargesq = 1 and 2. The MBED in the present form is found to work well for 11 ionic targets ranging from Be+ to K+ and complements its previous version valid for targets withq s> 2

The 16O + 12C elastic scattering data have been well described, for the first time, with a shallow folded potential obtained from a single folding method. The constituent parameters of the potential, excepting one, for its real part are generated from the nucleon–16O and α–16O potentials, and the cluster structure of 12C. Only the repulsive part of the α–16O potential needs some adjustment to fit the data, reflecting the need to include the Pauli exclusion effects among the unclustered nucleons.

A modification of the Kolbensvedt model, MKLV, in terms of ionic, correlation (between the incident and target electrons) and relativistic corrections, is proposed to calculate the K-shell electron impact ionization cross-sections of neutral and ionic targets. The modified model, with a single set of parameters, is found to reproduce satisfactorily the experimental data for the neutral H, Al, Ar, Mn, Ge, Mo, Ag, Sn, Au, Bi and U and ionic Li + , B 4+ and O 7+ targets better than the existing empirical models from threshold energies to as high as 10 4 MeV. For the Ag target, the calculations from MKLV follow closely the results of Scofield, and for Au, those of Scofield, and Ndefru and Malik, both done in the relativistic Born approximation with the Moller interaction, at energies higher than the peak region.

The present work reports the analyses of the experimental differential cross-sections of α elastic scattering on 58,60,62,64 Ni, over a wide range of incident energies, in terms of four types of optical potentials, namely shallow (molecular), deep non-monotonic, squared Woods–Saxon and semi-microscopic folding. All the four potentials produce a reasonable description of the experimental data. The potential parameters, calculated from the energy density functional theory using a realistic two-nucleon interaction, resemble closely the molecular potential parameters, which produce the best description of the experimental data for the four isotopes. The volume integrals and the energy variation of the parameters indicate the effect of the shell-model structure on the potentials. The folding potentials, without any need for renormalization, are found to describe reasonably well the elastic scattering cross-section data for the four isotopes within the energy range considered. In conformity with the previous observation on Ca isotopes, the number of nucleons, 4 A α = 49 , existing in α -like clusters in the target nucleus, is the same for the four isotopes, considered herein.

The differential cross sections for the elastic scattering of α particles by 40,44,48 Ca, over a wide range of incident energies, have been analyzed using a deep as well as shallow non-monotonic optical potential and compared with those using a squared Woods–Saxon (SWS) potential. The shallow non-monotonic potential exhibits a volume integral for the real part, characteristic of a molecular potential. The parameters of the SWS potential have also been obtained for α – 48 Ca scattering. The parameters of the shallow non-monotonic potential calculated from the energy-density-formalism provide a satisfactory description of the elastic scattering data. The non-monotonic potentials, both deep and shallow, are found to yield consistently a lower value of the radius parameter of the real potential for 48 Ca than that for 40 Ca, in conformity with the observed magnitudes of the root-mean-square radii for the two nuclei. Both the potentials indicate that the semi-magic 44 Ca behaves differently from the doubly-magic 40,48 Ca, in agreement with the findings from the folding potentials. The dispersion effect arising from the causality principle has been investigated for the shallow non-monotonic α – 40 Ca potential and is found to play a rather minor role in describing the elastic scattering data.

The electron impact single ionization cross-sections on the Be, B+, C2+, N3+, O4+, Ne6+, Fe22+ and U88+ atomic targets, in the beryllium isoelectronic sequence (BIS), are calculated using the modified versions of simplified improved binary-encounter dipole model (siBED) [W.M. Huo, Phys. Rev. A 64 (2001) 042719]. The modified models, QIBED (with the ionic correction) and RQIBED (with both the ionic and relativistic corrections) [M.A. Uddin, A.K.F. Haque, A.K. Basak, B.C. Saha, Phys. Rev. A 70 (2004) 032706], are found to provide an excellent description of the experimental data for all the targets in BIS with the same generic values of the two parameters d 1 and d 2 in the models. The RQIBED results describe satisfactorily the assessed data of Be and its predictions for U88+ account for well the experimental K-shell ionization data of Sn, with almost the same properties of the ionized orbit concerned, even up to around 2 MeV.

The experimental data of the 28Si(α, t)29P and 28Si(α, 3He)29Si reactions at 45 MeV have been analysed in terms of full finite-range coupled-channels calculations. In the calculations, the reaction paths, direct and two step via the inelastic states of the initial and final nuclei have been treated in terms of the finite-range transfer theory. The spectroscopic amplitudes connecting the deformed initial and final nuclei in both the reactions are obtained from Nilsson's model. The data of both the reactions, populating the 1/2+, 3/2+ and 5/2+ states in the Kπ = 1/2+ band and the 3/2+ and 5/2+ states in the Kπ = 3/2+ band, are best described by about 20% mixing of between the two bands. The effects of normal Woods–Saxon (WS), squared WS and molecular type of α-nucleus potentials are also discussed.

A simple modification of the empirical model of Hombourger (HEMP) [1998 J. Phys. B 31 3693] is proposed with ionic and relativistic corrections in it. The modified HEMP (MHEMP) model has been applied to 11 H- and He-like ionic targets with a wide range of atomic numbers Z = 5–92 to calculate the electron impact single ionization (EISI) cross sections. MHEMP with a single set of parameter values is found to describe excellently the experimental EISI cross sections of B4+, C4+, N6+, O7+, Ne8+, Mo41+, Dy65+, Au78+, Bi82+, U90+ and U91+ up to an incident energy of about 460 keV.

The electron impact single ionization cross-section of light ionic targets with multiple charges greater than 2 is evaluated employing two distinct modifications of the binary-encounter dipole (BED) model, the intermediate BEDTG and the modified BED (MBED) models. BEDTG incorporates the ionic correction due to Thomas and Garcia, whereas MBED embodies modification of the Burgess denominator along with the ionic correction. The differential continuum oscillator strengths are obtained adopting the analytic fits to available photo-ionization cross-sections, calculated quantum mechanically. To assess the reliability of these proposed modifications, a few simple targets, e.g., C 3+ ,N 4+ ,O 4+ ,O 5+ ,N e 6+ and Ne 7+ with known reliable theoretical results, are considered. Although the present MBED model seems to underestimate systematically the experimental data above 10 keV, it explains the data in the threshold and peak regions reasonably well with its predictions close to those from the Coulomb–Born approximation, convergent-close-coupling, distorted wave Born approximation withR-matrix, time-dependent andR-matrix pseudostate methods.

The cross sections for electron-impact single ionization of helium-like targets,—Li+, B3+, C4+, N5+, O6+, Ne8+, Na9+, Fe24+, Ag45+, and U90+—are calculated using a recently propounded parameter-free relativistic binary encounter (RBEA) model, which remains valid up to the relativistic energy domain. Our RBEA results are compared with those of the Coulomb–Born (CB) approximation, distorted wave Born approximation (DWBA), relativistic two-potential DWBA (RTPD), the simple empirical model of Brenshtam et al. (BRY), and the model of Deutsch and Mark (DM) along with the available experimental data. The RBEA model, while keeping the comparable predictive power of cross sections, is found to overcome the limitations of the empirical BRY and DM models with their fitting parameters, and the quantum mechanical CB, DWBA, and RTPD theories with arduous and lengthy calculations. © 2004 Wiley Periodicals, Inc. Int J Quantum Chem, 2004

A folding potential describing the $\alpha$ -scattering on 16O over a broad energy range 25.8-146.0 MeV is constructed on the basis of $\alpha$ -like cluster and unclustered-nucleon configurations of 16O. The resulting potential does not need any renormalization to fit the angular distribution of elastic cross-sections. The effects of the repulsive part of $\alpha$ - $\alpha$ and $\alpha$ -nucleon interactions are investigated. The analysis suggests that both the $\alpha$ - $\alpha$ repulsive potential and the unclustered nucleonic configuration in the target are important to describe the scattering data over a broad range of incident energies. The root-mean-square radius for the 16O nucleus is deduced.

The α elastic scattering on “non-alpha cluster” nuclei 44,48 Ca as well as their “alpha cluster” isotope 40 Ca has been successfully described by a potential derived from a single-folding model, in which the most of the nucleons in a nucleus exist in α-like clusters and the rest, in an unclustered nucleonic configuration. The folding potential does not need any renormalization factor over broad ranges of incident energies. The number of nucleons existing in the α-like clusters in the three Ca-isotopes has been found to be same and deduced as 34.

The differential cross-section of the 27Al(α, t)28Si reaction for 64.5 MeV incident energy has been reanalysed in DWBA with full finite range using a squared Woods–Saxon (Michel) α-nucleus potential with the modified value of the depth parameter α = 2.0 as reported in a comment article by Michel and Reidemeister. This new value produces significant improvement in fitting the data of the reaction with its overall performance, in some cases, close to that previously observed for the molecular potential. Although the non-monotonic shallow molecular potential with a soft repulsive core and the Michel potentials produce the same quality fits to the elastic scattering and non-elastic processes, they are not phase equivalent. The two types of potential produce altogether different cross-sections, particularly at large reaction angles. The importance of the experimental cross-sections at large angles for both elastic scattering and non-elastic processes is elucidated.

The total cross-sections of electron impact single K-shell ionization of C, N, O, Cr, Mn, Fe, Cu, Ga, Ge and Zr atoms are computed using the previously propounded relativistic and non-relativistic BED, relativistic DM and Gryzinski models. We also propose a hybrid RDM model combining the relativistic component of the Gryzinski model with the non-relativistic DM model. The calculated cross-sections are compared to the available experimental data as well as some predictions, made by Khare et al, from the plane wave Born approximation theory.

Previously developed BEB, RBEB, DM and recently developed RDM models are employed for the computation of cross-sections of electron impact single K-shell ionization of atoms with atomic numbers from Z = 19 to 103 to augment the work recently done involving atoms with Z = 6 to 40. The calculated cross-sections are compared with the available experimental data over a wide energy range up to 1000 MeV. The RDM model with simple relativistic factor is found to be at least as good as the DM model with a more complex factor up to about 60 MeV. However, the latter one is found to work satisfactorily up to about 1000 MeV.

Full finite-range macroscopic calculations in the distorted-wave Born approximation have been performed using the molecular and Michel α-nucleus potentials to analyze the angular distributions of cross-sections of the 27Al(α, d)29Si reaction, at 26.5 and 27.2 MeV incident energies, leading to seven transitions up to the excitation energy E X = 4.08 MeV of the final nucleus. The parameters of the two types of the α-nucleus potentials are determined from the elastic-scattering data. Both the molecular and Michel potentials, without any adjustment to the parameters needed to fit the elastic-scattering data, are able in most cases to reproduce, simultaneously, the absolute cross-sections particularly at large angles, where the previous calculations failed to reproduce by orders of magnitude, and the gross pattern of angular distributions of the reaction. The deuteron-cluster spectroscopic factors for most of the seven transitions, deduced using the two α-27Al potentials, differ from those obtained in earlier works. The spectroscopic factor for the ground-state transition, deduced in the present work for the 25.8 MeV data, agrees well with the shell model prediction.

The spin-polarization S and the spin-polarization parameters U and T of the elastically scattered electrons from Hg atoms have been computed for scattering angles 0°–180° in the energy range 1 eV . An optical model approach is employed using a complex optical potential within the framework of the Dirac relativistic partial wave analysis. We compare our results with recent experiments and available theoretical calculations and find a reasonable agreement with experiments over a wide range of energies.

We report an extension and modification of the MCN model of Haque et al (2013 Rad. Phys. Chem. 91 50–9) (XMCN) to study the electron impact ionization of inner L and M shells of neutral atoms by introducing new parameters of the MCN model. The extended XMCN model, including the relativistic effect, has been applied with success to evaluate ionization cross-sections of various atomic targets with Z = 38–92 for both individual subshells and total L-shell and the corresponding cross-sections for the M shell for Z = 79–92 at incident energies E Threshold 1 GeV. A comparison with other available theoretical and experimental cross-sections reveals that our results reproduce the experimental measurements with a reasonable accuracy.

Effects of three different α-nucleus potentials, the normal Woods-Saxon (WS), the squared WS and the molecular, have been studied using the differential cross-section data of inelastically scattered α-particles on 24Mg and 28Si at 54 and 26 MeV incident energies, respectively. The angular distributions of inelastic scattering to the first 2+ and 4+ states of the two nuclei have been analyzed in terms of a coupled-channel formalism. The macroscopic rotational model using both the squared WS and the molecular potentials can produce satisfactorily a simultaneous description of the elastic data and the inelastic-scattering data of the 2+ and 4+ states for both the targets. The normal WS potential fails to describe the elastic and inelastic data, simultaneously. The effects of second-order deformed potential are also investigated. Microscopic coupled-channel calculations, using the 0+-2+ coupling and the Gaussian α-nucleon interaction in the form-factor, have also been performed for the 28Si target using both the squared WS and molecular potentials, the latter one giving a reasonable description of the data.

The DWBA analyses are performed for the ground states and other strong transitions populated in the (α, t) reaction on various targets ranging fromA = 16 to 208 with zero-range and with finite-range corrections in the local energy approximation (LEA). The normalization constants without and with the LEA are found to be, respectively,D 2 0 = (18.16±3.49) × 10 MeV fm andD = (8.67±1.60)× 10 MeV2 fm3 which are reasonably consistent with some other previous studies. The normalization constants for the (α, t) reaction on the Al target are also deduced for different incident energiesEα = 25.0, 25.2, 64.5, 80.0 and 104.0 MeV for studying any possible energy dependence of the normalization constant. No tangible energy dependence was found in the present study and hence the LEA seems to be valid reliably within the energy range studied. The ratioD 2 0/D bears a value of about 2.0 which is remarkably constant over the target masses and incident energies.