Related papers: Quadrupole Arrangements and the Ground State of So…
The unique isomeric transition at 7.8 eV in $~^{229}\mathrm{Th}$ has a magnetic dipole ($M1$) and an electric quadrupole ($E2$) multipole mixing. So far, the $E2$ component has been widely disregarded. Here, we investigate the nuclear…
We discuss the triple-$\vec{q}^X$ structures for the ordered cubic phase of NpO$_2$, which are $Pn{\bar 3}m$ and $Pa{\bar 3}$. A special care should be taken to discriminate between these two cases. We analyze the relevant structure-factor…
Solid-solid phase transitions in metals are traditionally driven by changes in density or external pressure. Here we show that, under strong electronic excitation, structural stability is governed by the interplay between electronic effects…
We study a spin system with two- and four-spin exchange interactions on the triangular lattice, which is a possible model for the nuclear magnetism of solid $^3$He layers. It is found that a novel spin structure with scalar chiral order…
A series expansion of the interaction between a nucleus and its surrounding electron distribution provides terms that are well-known in the study of hyperfine interactions: the familiar quadrupole interaction and the less familiar…
The crystal structure of high-pressure solid hydrogen remains a fundamental open problem. Although the research frontier has mostly shifted toward ultra-high pressure phases above 400 GPa, we show that even the broken symmetry phase…
The nonrelativistic energies of the homonuclear ion T$_2^+$ are calculated for the ground state using the Lagrange-mesh method as was done for the isotopomers H$_2^+$ and D$_2^+$ ({\it J. Phys. B: At. Mol. Opt. Phys.} {\bf 45} 065101 and…
We theoretically study electric quadrupole orders in f-electron systems on the fcc lattice. Qudrupole degrees of freedom $O_{20}$ and $O_{22}$ originate in the non-Kramers doublet ground state $\Gamma_3$ of ion with $f^2$ electron…
We investigate the charge and lattice states in a quasi-one-dimensional organic ferroelectric material, TTF-QCl$_{4}$, under pressures of up to 35 kbar by nuclear quadrupole resonance experiments. The results reveal a global…
The high-pressure II-III phase transition in solid hydrogen is investigated using the random phase approximation and diffusion Monte Carlo. Good agreement between the methods is found confirming that an accurate treatment of exchange and…
We examine the role of charge, structural, and spin degrees of freedom in the previously poorly understood phase transition in the 5$d^1$ transition-metal double perovskite Cs$_2$TaCl$_6$, using a combination of computational and…
We investigate the stability of the square vortex lattice which has been recently observed in experiments on the borocarbide family of superconductors. Taking into account the tetragonal symmetry of these systems, we add fourfold symmetric…
The frequency dependence of dynamical conductivity of the quasi-one-dimensional structures with hydrogen bonds is studied on the basis of pseudospin-electron model. It takes into account the proton-electron interaction, external…
We present a theoretical model of the "isostructural" \gamma-\alpha phase transition in Ce which is based on quadrupolar interactions due to coupled charge density fluctuations of 4f electrons and of conduction electrons. Conduction…
Relativistic formulas for the electric quadrupole moment of a hydrogenlike atom, induced by the hyperfine interaction, are derived for $ns_{1/2}$ and $np_{1/2}$ states. Both the magnetic dipole and electric quadrupole hyperfine interactions…
We study the effect of temperature up to 1000K on the structure of dense molecular para-hydrogen and ortho-deuterium, using the path-integral Monte Carlo method. We find a structural phase transition from orientationally disordered…
Large scale ab initio calculations of the electric contribution (i.e. the electric field gradient) to the electric quadrupole hyperfine interaction constants $B$ for the $5p~^2P_{3/2}$ state in $^{109}$Cd$^+$ ion and the $5s5p~^3P_{1,2}$…
The existence of electronic symmetry breaking in the underdoped cuprates, and its disappearance with increased hole-density $p$, are now widely reported. However, the relationship between this transition and the momentum space…
To understand the pressure-induced changes in the electronic structure and the electron-phonon interaction in yttrium, we have studied hexagonal close-packed (hcp) yttrium, stable at ambient pressure and double hexagonal close-packed (dhcp)…
Treating water as a linearly responding dielectric continuum on molecular length scales allows very simple estimates of solvation structure and thermodynamics for charged and polar solutes. While this approach can successfully account for…