The $\ensuremath{\alpha}$-particle cluster structure of $^{44}\mathrm{Ti}$, which is considerable interest for investigation the persistence $\ensuremath{\alpha}$ clustering in region $\mathrm{sd}$-shell closure, studied within frame a local-potential approach. It shown that model leads to specific predictions if continuity with existing unique $\ensuremath{\alpha}+^{40}\mathrm{Ca}$ optical potentials \"{\i}s insisted upon; particular, existence an as yet experimentally unknown...

We investigate the linear chain configurations of four-$\ensuremath{\alpha}$ clusters in $^{16}\mathrm{O}$ using a Skyrme cranked Hartree-Fock method and discuss relationship between stability such states angular momentum. show existence region momentum ($13--18\ensuremath{\hbar}$) where configuration is stabilized. For first time we demonstrate that stable exotic with large moment inertia (${\ensuremath{\hbar}}^{2}/2\ensuremath{\Theta}\ensuremath{\sim}0.06--0.08\text{ }\text{...

We review the merits of local potential approach in description elastic alpha-particle scattering and alpha-cluster structure medium-weight nuclei. recall how optical model analyses angular distributions, displaying an anomalous large angle enhancement, yielded unique potentials, whose real part is determined with good accuracy up to small internucleus distances, we investigate their properties; then analyze general compatibility these potentials microscopic requirements resulting from...

Elastic scattering of α-particles and some tightly bound light nuclei has shown the pattern rainbow at medium energies, which is due to refraction incident wave by a strongly attractive nucleus–nucleus potential. This review gives an introduction physics nuclear based essentially on optical model description elastic scattering. Since realistic potential (OP) key explore this interesting process, overview main methods used determine OP presented. Given fact that absorption in system much...

The \ensuremath{\alpha}-particle clustering structure of ${}^{94}$Mo and ${}^{212}$Po, which is interest for investigating the persistence \ensuremath{\alpha} in heavy nuclei, studied within framework a local potential approach using double folding model. It shown that model, describes scattering from ${}^{90}$Zr well, locates ground state at energy corresponding to experiment. A similar result was obtained $\ensuremath{\alpha}{+}^{208}\mathrm{Pb}$ system. found model gives not only band...

It is shown that the dilute density distribution of $\ensuremath{\alpha}$ particles in nuclei can be observed Airy structure nuclear rainbow scattering. We have analyzed $\ensuremath{\alpha}+^{12}\mathrm{C}$ scattering to ${0}_{2}^{+}\phantom{\rule{0.3em}{0ex}}(7.65\phantom{\rule{0.3em}{0ex}}\mathrm{MeV})$ state $^{12}\mathrm{C}$ a coupled-channel method with precise wave functions for $^{12}\mathrm{C}$. found enhanced oscillations experimental angular distributions ${0}_{2}^{+}$ caused by...

\ensuremath{\alpha}-cluster states in $^{44}\mathrm{Ti}$ have been investigated the $^{40}\mathrm{Ca}$${(}^{6}$Li,d${)}^{44}$Ti reaction at E=50 MeV. The angular distributions of 34 levels excitation energies for ${\mathit{E}}_{\mathit{x}}$=0--13 MeV allow us to analyze data. positive-parity members ground-state band (the ${\mathit{K}}^{\mathrm{\ensuremath{\pi}}}$=${0}^{+}$ band) were well reproduced by finite-range distorted-wave Born approximation calculations up transferred momentum L=8....

The \ensuremath{\alpha}-cluster structure of the $^{44}\mathrm{Ti}$ nucleus is investigated within a local potential model description, starting from unique optical which describes elastic $^{40}\mathrm{Ca}$(\ensuremath{\alpha},\ensuremath{\alpha}) scattering on broad angular and energy ranges, has recently been shown to describe oscillations seen in low fusion excitation function as well. It found that various states group into quasirotational bands whose properties are not dissimilar those...

Evidence for the existence of lowest $N=24$ and $N=28$ cluster bands with ${}^{16}\mathrm{O}{+}^{16}\mathrm{O}$ structure in ${}^{32}\mathrm{S}$ is shown from viewpoint unified description bound scattering states system. The band structure, gross $90\ifmmode^\circ\else\textdegree\fi{}$ excitation function ${\mathrm{for}}^{16}\mathrm{O}{+}^{16}\mathrm{O}$ elastic scattering, Airy minima are understood a way. unobserved $N=26$ higher nodal predicted.

An extended optical potential model is proposed, which has a parity-dependent part in the nuclear surface region. Backward angle anomaly differential cross section appearing α-particle scattering on nuclei calcium region analyzed systematically by this model. It shown that amplitudes of sufrace-grazing partial waves superposed are summed up coherently at backward angles to give rising section. The α-Ca and -Ar with an incident energy near 20 ∼30 MeV fairly good fit obtained. gross behavior...

We investigate the possibility of existence exotic torus configuration in high-spin excited states $^{40}\mathrm{Ca}$. here consider spin alignments about symmetry axis. To this end, we use a three-dimensional cranked Skyrme Hartree-Fock method and search for stable single-particle configurations. find one state with at total angular momentum $J=60\text{ }\ensuremath{\hbar}$ an excitation energy 170 MeV all calculations using various interactions. The consists aligned 12 nucleons orbital...

The \ensuremath{\alpha}${+}^{40}$Ca system is investigated in the framework of folding model using Hasegawa-Nagata-Yamamoto effective two-body force. It shown that potential which can bind not only higher nodal band with cluster structure but also ground-state describe well scattering a wide energy range ${E}_{\ensuremath{\alpha}}$=18--100 MeV. A critique \ensuremath{\alpha}-cluster theory $^{44}\mathrm{Ti}$ an interaction cannot given.

Alpha-cluster states in 40Ca, 44Ti and 94Mo have been investigated by the 36Ar(6Li,d)40Ca at E = 50 MeV, 40Ca(6Li,d)44Ti reaction 37 MeV 90Zr(6Li,d)94Mo MeV. Parity-doublet bands 40Ca successfully established, while trial to obtain angular distributions of was unsuccessful. This report reviews our experimental search for α-clustering A ≥ 40 nuclei. For nucleus, positive-parity members ground-state band (the Kπ 0+ band) were well reproduced finite-range distorted-wave Born approximation...

Rainbows are generally considered to be caused by static refraction and reflection. A primary a secondary rainbow appear due internal reflection in raindrop as explained Newton. The quantum nuclear rainbow, which is generated the nucleus droplet, only has "primary" rainbow. Here we show for first time evidence existence of dynamically coupling an excited state without This been demonstrated experimental $^{16}$O+$^{12}$C scattering using coupled channel method with extended double folding...

The physical interpretation of nuclear rainbow scattering within the frame optical model is critically investigated. Starting from properties Luneburg lens, a gradient index device that displays refractive features similar to those potential, important differences between mechanisms producing and rainbows are pointed out.

We formulate a model for $^{212}\mathrm{Po}$, based on the coupled-channels of $\ensuremath{\alpha}+{}^{208}\mathrm{Pb}$(${0}^{+}$) and $\ensuremath{\alpha}+{}^{208}\mathrm{Pb}$(${3}^{\ensuremath{-}}$) in which $\ensuremath{\alpha}$-Pb interaction contains scalar, quadrupole, octupole terms. The reproduces recently observed enhanced $E1$ transitions from several new negative-parity levels to yrast states. Because these data are hard understand shell model, this success gives strong support...

Angular distributions for elastic and inelastic scattering of $^3$He from $^{12}$C were measured at energies 50.5 60 MeV. The Airy minimum the prerainbow was clearly observed in angular 0$_2^+$ (7.65 MeV) state (Hoyle state). experimental results analyzed with a coupled channels method double folding potentials derived microscopic wave functions ground 0$_1^+$, 2$^+$ (4.44 MeV), 3$^-$ (9.64 states. analysis supports view that Hoyle is three alpha particle condensate large radius dilute...

The structure of the nuclei in mass range 40 ≤ A 44 is investigated by microscopic α + core orthogonality condition model. energy spectra, electromagnetic transitions and α-spectroscopic factors are calculated. calculated properties good overall agreement with available experimental data. It shown that α-cluster states yield similar rotational bands which characterized weak coupling feature parity-doublet. observed E2 intra-band cluster bands, show strong enhancement, other systematically...

The backward angle anomaly in α-particle scattering from 36Ar is analyzed by using a deep potential. It found that the potential which describes α+ reproduces well K=01+ rotational band of 40Ca. inevitably predicts K=0- with cluster structure above threshold counterpart inversion doublet band.