Theoretical study of LiCl− and LiBr− molecular ions

The molecular structures and spectroscopic constants of the ground electronic states of LiCl^? and LiBr^? are investigated with the coupled-cluster method. To improve the accuracy of our calculations, we have employed the extrapolation schemes as well as corrections of the core–valence correlation and scalar relativistic effect. The equilibrium parameters, potential energy curves, force constants, vibrational energy levels and spectroscopic parameters of both molecular ions are derived, in which those of LiBr^? are reported for the first time. The electron affinities and vertical detachment energies of neutral and anionic LiCl and LiBr are also evaluated.     

Ab initio study of the Ar–CS2(V1B2) intermolecular potential surface: effect of van der Waals interaction on the emission of CS2 molecule

In this work, the excited state intermolecular potential energy surface of the Ar–CS₂(V¹B₂) van der Waals complex was evaluated for the first time. The calculation of more than 4000 single-point interaction energies for the complex using an equation-of-motion coupled-cluster model with single and double substitutions level of theory with extended basis set involving bond functions has been performed. After fitting the interaction energies to analytical functions, the emission spectra of the Ar–CS₂(V¹B₂) complex related to the different stationary points on the potential energy surface were calculated. It was seen that the intensity and the position of the emission spectra are dependent on the orientation of the Ar atom around the bent excited CS₂ and the distance between two components. The information about the structural parameters of the complex related to the global minimum was obtained under the pseudodiatomic approximation with assistance of ab initio potential. The presented investigation could be useful for further theoretical and experimental studies of Ar–CS₂(V¹B₂) complex.     

Prediction and characterisation of a chalcogen···π interaction with acetylene as a potential electron donor in XHS···HCCH and XHSe···HCCH (X = F,Cl, Br,CN, OH,OCH3, NH2, CH3) σ-hole complexes

It is well-known that many covalently bonded atoms of group VI have specific positive regions of electrostatic potential (σ-holes) through which they can interact with Lewis bases. This interaction is called ‘chalcogen bond’ by analogy with halogen bond and hydrogen bond. In this study, ab initio calculations are performed to predict and characterise chalcogen···π interactions in XHS···HCCH and XHSe···HCCH complexes, where X = F, Cl, Br, CN, OH, OCH₃, NH₂, CH₃. For the complexes studied here, XHS(Se) and HCCH are treated as a Lewis acid and a Lewis base, respectively. The CCSD(T)/aug-cc-pVTZ interaction energies of this type of σ-hole bonding range from ?1.18 to ?4.83 kcal/mol. The calculated interaction energies tend to increase in magnitude with increasing positive electrostatic potential on the extension of X–S(Se) bond. The stability of chalcogen···π complexes is attributed mainly to electrostatic and correlation effects. The nature of chalcogen···π interactions is unveiled by means of the atoms in molecules, natural bond orbital, and electron localisation function analyses.     

Splitting of Spectra in Anharmonic Oscillators Described by Kratzer Potential Function

A perturbation theory model that describes splitting of the spectra in highly symmetrical molecular species in electrostatic field is proposed. An anahrmonic model of a two-dimensional oscillator having Kratzer potential energy functionis used to model the molecular species and to represent the unperturbed system. A selection rule for the radial quantum number of the oscillator is derived. The eigenfunctions of a two-dimensional anharmonic oscillator in cylindrical coordinates are used for the matrix elements representing the probability for energy transitions in dipole approximation to be calculated. Several forms of perturbation operators are proposed to model the interactionbetween the polyatomic molecular species and an electrostatic field. It is found that the degeneracy is removed in the presence of the electric field and spectral splitting occurs. Anharmonic approximation for the unperturbed system is more accurate and reliable representation of a real polyatomic molecular species.     

Nuclear structure around ~(80)Zr

Recent years have witnessed intense activity concerning the study of nuclei with equal numbers of neutrons and protons (N = Z). Exotic properties have been exhibited in the N = Z nuclei, especially in those with atomic masses around 80. In the present paper, the projected shell model(PSM)together with a relativistic Hartree-Bogoliubov (RHB) theory is used to study the nuclear structure near the N = Z line in the mass A ≈ 80 region. For three Zr isotopes 80,82,84Zr, the projected potential energy surfaces and ground state bands are calculated. It is shown that shape coexistence occurs in all of these nuclei. Moreover, we find that the residual neutron-proton interaction strongly affects the ground state band of 80Zr; however, it slightly modifies those of 82Zr and 84Zr.     

Aharonov–Bohm effect for bound states on spin-0 massive charged particles in a Gödel-type space–time with Coulomb potential

In this paper, we investigate the relativistic quantum dynamics of spin-0 massive charged particles in a Gödel-type space–time with electromagnetic interactions. We derive the radial wave equation of the Klein–Gordon equation with an internal magnetic flux field and Coulomb-type potential in the Som–Raychaudhuri space–time with cosmic string. We solve this equation and analyze the analog effect in relation to the Aharonov–Bohm effect for bound states.     

Discrete breathers in a model with Morse potentials

Under harmonic approximation, this paper discusses the linear dispersion relation of the one-dimensional chain. The existence and evolution of discrete breathers in a general one-dimensional chain are analysed for two particular examples of soft (Morse) and hard (quartic) on-site potentials. The existence of discrete breathers in one-dimensional and two-dimensional Morse lattices is proved by using rotating wave approximation, local anharmonic approximation and a numerical method. The localization and amplitude of discrete breathers in the two-dimensional Morse lattice with on-site harmonic potentials correlate closely to the Morse parameter a and the on-site parameter к.     

Leucine-coated cobalt ferrite nanoparticles: Synthesis,characterization and potential biomedical applications for drug delivery

This work was primarily focused on the synthesis, characterization and biomedical applications of cobalt ferrite (CoFe₂O₄) nanoparticles, which were synthesized by a facile solvothermal method using an amino acid of Leucine (Leu) as the surface coating agents. The morphology, structure and properties of the as-synthesized uncoated and Leu-coated CoFe₂O₄ nanoparticles were characterized in detail by means of XRD, SEM, TEM, DLS, FTIR, XPS, TGA and SQUID. More importantly, it was found that the Leu-coated CoFe₂O₄ nanoparticles can be used as the efficient drug delivery with a drug loading capacity of 0.32 mg/mg for doxorubicin hydrochloride (DOX), and the loaded DOX demonstrated a sustained and progressive release manner. The in vitro cytotoxicity studies towards the HeLa cells were carried out, and the results indicated that the Leu-coated CoFe₂O₄ nanoparticles exhibited a relatively high cell viability compared with that of bare CoFe₂O₄ nanoparticles and the DOX loaded Leu-coated CoFe₂O₄ nanoparticles presented an obvious cytotoxic effect on HeLa cells.     

A new approach to solve the one-dimensional Schrödinger equation using a wavefunction potential

A new approach to find exact solutions to one–dimensional quantum mechanical systems is devised. The scheme is based on the introduction of a potential function for the wavefunction, and the equation it satisfies. We recover known solutions as well as to get new ones for both free and interacting particles with wavefunctions having vanishing and non–vanishing Bohm potentials. For most of the potentials, no solutions to the Schrödinger equation produce a vanishing Bohm potential. A (large but) restricted family of potentials allows the existence of particular solutions for which the Bohm potential vanishes. This family of potentials is determined, and several examples are presented. It is shown that some quantum, such as accelerated Airy wavefunctions, are due to the presence of non–vanishing Bohm potentials. New examples of this kind are found and discussed.