Partial dynamical symmetry versus quasi dynamical symmetry examination within a quantum chaos analyses of spectral data for even–even nuclei

Statistical analyses of the spectral distributions of rotational bands in 51 deformed prolate even–even nuclei in the 152 ≤ A ≤ 250 mass region $$R_{{4_{1}^{ + } /2_{1}^{ + } }} \ge 3.00$$ R 4 1 + / 2 1 + ≥ 3.00 are examined in terms of nearest neighbor spacing distributions. Specifically, the focus is on data for 0+, 2+, and 4+ energy levels of the ground, gamma, and beta bands. The chaotic behavior of the gamma band, especially the position of the $$2_{\gamma }^{ + }$$ 2 γ + band-head compared to other levels and bands, is clear. The levels are analyzed within the framework of two models, namely, a SU(3)-partial dynamical symmetry Hamiltonian and a SU(3) two-coupled quasi-dynamical symmetry Hamiltonian, with results that are further analyzed using random matrix theory. The partial and quasi dynamics both yield outcomes that are in reasonable agreement with the known experimental results. However, due to the degeneracy of the beta and gamma bands within the simplest SU(3) picture, the theory cannot be used to describe the fluctuation properties of excited bands. By changing relative weights of the different terms in the partial and quasi dynamical Hamiltonians, results are obtained that show more GOE-like statistics in the partial dynamical formalism as the strength of the pairing term is increased. Also, in the quasi-dynamical symmetry limit, more correlations are found because of the stronger couplings.

Electronic transitions in Rb2+ dimers solvated in helium

We have measured depletion spectra of the heteronuclear (85Rb87Rb+) dimer cation complexed with up to 10 He atoms. Two absorption bands are observed between 920 and 250 nm. The transition into the repulsive 12Σu+ state of HeRb2+ gives rise to a broad feature at 790 nm (12,650 cm−1); it exhibits a blueshift of 98 cm−1 per added He atom. The transition into the bound 12Πu state of HeRb2+ reveals vibrational structure with a band head at ≤ 15,522 cm−1, a harmonic constant of 26 cm−1, and a spin–orbit splitting of ≤ 183 cm−1. The band experiences an average redshift of − 38 cm−1 per added He atom. Ab initio calculations rationalize the shape of the spectra and spectral shifts with respect to the number of helium atoms attached. For a higher number of solvating helium atoms, symmetric solvation on both ends of the Rb2+ ion is predicted.

Examination of phenomenological formulae in superdeformed bands of A ∼ 190,150 mass regions

The rotational energy formulae viz. VMI model, ab-formula, Harris [Formula: see text] expansion, Exponential model with pairing attenuation and Nuclear softness formula are employed to the superdeformed bands of [Formula: see text] and [Formula: see text] mass regions in order to test the validity of various rotational energy formulae in describing the general nature of superdeformed bands. These formulae are used to deduce the band-head spins of the nine superdeformed bands in [Formula: see text] mass region and two superdeformed bands of [Formula: see text] mass region. The band-head spins of these superdeformed bands have been established experimentally and hence they prove to be excellent candidates to examine the adequacy of rotational energy formulae in superdeformed bands. The least-squares fitting of [Formula: see text]-transition energies is performed to calculate the model parameters such as the band-head moment of inertia, the effective pairing gap parameter and the softness parameter, and a careful analysis of these parameters is made. For the first time, we have performed a systematic study of the rotational energy formulae to establish which formula gives the best estimate of spin in [Formula: see text] mass regions.

Spectroscopic investigation of non-thermal plasma generated in atmospheric pressure ‘Plasma Pencil’

Plasma generated at atmospheric pressure has widespread applications in the field of plasma medicine. In this paper, spectroscopic investigations of homemade capacitively coupled, atmospheric pressure RF plasma pencil is reported. Optical emission spectroscopy (OES) technique is employed to characterize the plasma. Variation in rotational/gas temperature [Formula: see text], [Formula: see text] atomic density, dissociation fraction [Formula: see text] and normalized intensities of [Formula: see text], [Formula: see text] and [Formula: see text] radiation is monitored as a function of discharge parameters like RF power and different gases concentration. [Formula: see text] of [Formula: see text] mixture is estimated from [Formula: see text] band head of R branch of first negative system of nitrogen [Formula: see text], [Formula: see text], [Formula: see text] using Boltzmann plot technique. Similarly, [Formula: see text] band head of second positive system (SPS) of nitrogen [Formula: see text], [Formula: see text], [Formula: see text] is also used to estimate [Formula: see text] by fitting synthetic spectra over the experimentally recorded spectrum. It is noted that [Formula: see text] increases with increase in RF power, but it decreases with increase in [Formula: see text] concentration in the mixture. [Formula: see text] atomic density and dissociation fraction [Formula: see text], estimated from [Formula: see text] line at 750 nm and [Formula: see text] line at 844 nm using actinometry technique, show increasing trend with RF power and [Formula: see text] concentration in the mixture up to 0.7% [Formula: see text] in the mixture. The normalized [Formula: see text] radiation intensities; [Formula: see text], [Formula: see text] and [Formula: see text] show the increasing trend with increase in RF power up to 0.3% [Formula: see text] concentration in the mixture.

Moments of Inertia of SDIBs in A = 190 Mass Region using VMI Model

A lot of identical bands are known at present in the Normal Deformed (ND) region. In our study of the occurrence and properties of identical bands in Super-Deformed (SD) nuclei we first applied the modified Variable Moment of Inertia (VMI) model to extract the band-head spin of Super-Deformed bands. The calculated transition energies, level spins and dynamic moment of inertia are systematically examined. Then, in the framework of theoretical model several identical bands are identified. The kinematic and dynamic moment of inertia have been calculated for the six pairs of Super-Deformed Identical Bands (SDIBs) which was not reported earlier in the literature. Thus, the results are significant. In all the cases J(2) is significantly higher than J(1) over a large range of frequency.

Band head spin assignment of superdeformed bands in 133Pr using two-parameter formulae

The two-parameter formulae viz. the power index formula, the nuclear softness formula and the VMI model are adopted to accredit the band head spin [Formula: see text] of four superdeformed rotational bands in [Formula: see text]. The technique of least square fitting is used to accredit the band head spin for four superdeformed rotational bands in [Formula: see text]. The root mean deviation among the computed transition energies and well-known experimental transition energies are attained by extracting the model parameters from the two-parameter formulae. The determined transition energies are in excellent agreement with the experimental transition energies, whenever exact spins are accredited. The power index formula coincides well with the experimental data and provides minimum root mean deviation. So, the power index formula is more efficient tool than the nuclear softness formula and the VMI model. The deviation of dynamic moment of inertia [Formula: see text] against the rotational frequency is also examined.