Related papers: Evidence for tetrahedral symmetry in 16O
We have investigated structures of the ground and excited states of $^{16}\textrm{O}$ with the method of variation after spin-parity projection in the antisymmetrized molecular dynamics model combined with the generator coordinate method of…
We discuss an algebraic treatment of four-body clusters which includes both continuous and discrete symmetries. In particular, tetrahedral configurations with T(d) symmetry are analyzed with respect to the energy spectrum, transition form…
A reinterpretation of the complete energy spectrum of the Oxygen-16 nucleus up to 20 MeV, and partly beyond, is proposed. The underlying intrinsic shape of the nucleus is tetrahedral, as in the na\"ive alpha-particle model and other cluster…
Theoretical predictions suggest the presence of tetrahedral symmetry as an explanation for the vanishing intra-band E2-transitions at the bottom of the odd-spin negative parity band in $^{156}Gd$. The present study reports on experiment…
More than 100 excited states of the Calcium-40 nucleus, with isospin 0, are classified into rotational-vibrational bands of an intrinsic tetrahedral structure. Almost all observed states below 8 MeV can be accommodated, as well as many…
Ba$_2$IrO$_4$ has been refined in the tetragonal $I4/mmm$ phase without octahedral rotations, and its physical properties have been interpreted in this high-symmetry structure. However, the dynamical stability of this undistorted phase has…
The possibility of the appearance of the C$_{4}$ symmetry in the rotational bands is studied within the particle-rotor model. Allowing for a slight triaxiality of the rotor it is shown that the lowest states of the system for a sufficiently…
We report on an experimental evidence for a new, second tetrahedral band in $^{152}_{\;\;62}$Sm$^{}_{90}$. It was populated via fusion evaporation reaction, $^{150}{\rm Nd}(\alpha, 2n)^{152}$Sm, employing 26 MeV beam of $\alpha$ particles…
Inherent nodal surfaces existing in the wavefunctions of intrashell states of 4-valence-electron atoms have been investigated. The decisive effect of these surfaces has been demonstrated, the ordering of low-lying levels has been predicted,…
We study 4$\alpha$ linear-chain states in 16O in comparison with 3$\alpha$ states in 12C by using the Generator Coordinate Method within a microscopic $N\alpha$-cluster model. It is shown to be very important to solve relative motion of…
Within the low-lying spectrum of 10Be, multiple rotational bands are found, with strikingly different moments of inertia. A proposed interpretation has been that these bands variously represent triaxial rotation and prolate axially-deformed…
We present ab initio lattice calculations of the low-energy even-parity states of $^{16}$O using chiral nuclear effective field theory. We find good agreement with the empirical energy spectrum, and with the electromagnetic properties and…
$\alpha$-cluster correlations in the $0^+_1$ and $3^-_1$ states of $^{12}$C and $^{16}$O are studied using the method of antisymmetrized molecular dynamics, with which nuclear structures are described from nucleon degrees of freedom without…
In this contribution, we present evidence for the occurrence of triangular symmetry in cluster nuclei. We discuss the structure of rotational bands for 3-alpha and 3-alpha+1 configurations with triangular D(3h) symmetry by exploiting the…
The existence of a rotational band with the $\alpha$+$^{12}$C($0_2^+$) cluster structure, in which three $\alpha$ particles in $^{12}$C($0_2^+$) are locally condensed, is demonstrated near the four-$\alpha$ threshold of $^{16}$O in…
We study nonlinear vibrational modes of oscillations for tetrahedral configurations of particles. In the case of tetraphosphorus, the interaction of atoms is given by bond stretching and van der Waals forces. Using equivariant gradient…
We report the observation and analysis of spectra in part of the near-infrared spectrum of C$_2$H, originating in rotational levels in the ground and lowest two excited bending vibrational levels of the ground $\tilde{X}\,^2\Sigma^+$ state.…
Low-energy vibrational excitations associated with the fluctuation of quadrupole deformed shapes are discussed within the frame of state-of-the-art Configuration Interaction calculations, actually performed via the Quasi-particle Vacua…
We report a measurement of a new high spin Jp = 5- state at 22.4(0.2) MeV in 12C which fits very well to the predicted (ground state) rotational band of an oblate equilateral triangular spinning top with a D_3h symmetry characterized by the…
A study of 4$\alpha$ linear-chain structure in high-lying collective excitation states of $^{16}$O with a covariant density functional theory is presented. The low-spin states are obtained by configuration mixing of particle-number and…