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Poly[[pentaaqua(μ4-pyridine-2,4,6-tricarboxylato)(μ3-pyridine-2,4,6-tricarboxylato)disamarium(III)] monohydrate]
The asymmetric unit of the title compound, {[Sm2(C8H2NO6)2(H2O)5]·H2O}n, contains two independent SmIII ions, two pyridine-2,4,6-tricarboxylate (ptc) ligands, five aqua ligands and one lattice water molecule. One SmIII ion is nine-coordinated by one N and five O atoms from the three ptc ligands and three aqua ligands in a distorted monocapped square antiprismatic geometry, and the other is eight-coordinated by one N and five O atoms from three ptc ligands and two aqua ligands in a 4,4′-bicapped trigonal antiprismatic geometry. The ptc ligands brigde the SmIII ions into a three-dimensional polymeric framework. Extensive O—H⋯O hydrogen bonding is observed in the crystal structure
The Wigner Solution and QCD Phase Transitions in a Modified PNJL Model
By employing some modification to the widely used two-flavor Polyakov-loop
extended Nambu-Jona-Lasinio (PNJL) model, we discuss the Wigner solution of the
quark gap equation at finite temperature and zero quark chemical potential
beyond the chiral limit, and then try to explore its influences on the chiral
and deconfinement phase transitions of QCD at finite temperature and zero
chemical potential. The discovery of the coexistence of the Nambu and the
Wigner solutions of the quark gap equation with nonzero current quark mass at
zero temperature and zero chemical potential, as well as their evolutions with
temperature is very interesting for the studies of the phase transitions of
QCD. According to our results, the chiral phase transition might be of first
order (while the deconfinement phase transition is still a crossover, as in the
normal PNJL model), and the corresponding phase transition temperature is lower
than that of the deconfinement phase transition, instead of coinciding with
each other, which are not the same as the conclusions obtained from the normal
PNJL model. In addition, we also discuss the sensibility of our final results
on the choice of model parameters
Exceptional entanglement in non-Hermitian fermionic models
Exotic singular objects, known as exceptional points, are ubiquitous in
non-Hermitian physics. They might be spectral singularities in energy bands
that produce anomalous effects and defectiveness. The quantum entanglement of a
generic non-Hermitian model with two different types of spectral exceptional
points (SEPs) is systematically investigated in this paper. We discovered a
relationship between non-unitary conformal field theories and the
-linear-type SEPs, which is typically associated with
-symmetry or pesdo-Hermicity spontaneous breaking. The underlying
association between -square-root-type SEPs, which arise concurrently with
real (imaginary) gap closing in the complex spectrum, mimicking
first-order-phase-transition criticalities, and complex conformal field
theories (cCFTs) is addressed through the calculation of complex central
charges. From the entanglement spectrum, zero-energy exceptional modes are
found to be distinct from normal zero modes or topological boundary modes.
Finally, we include a brief discussion of analogous non-Hermitian quantum spin
models and endeavor to establish an intuitive understanding of exceptional
points through the spin picture in various scenarios
Redetermined structure of oxaline: absolute configuration using Cu Kα radiation
In the title compound, C24H25N5O4, the stereogenic C atom bonded to three N atoms and one C atom has an S configuration and its directly bonded neighbour has an R configuration. An intramolecular N—H⋯O hydrogen bond supports the near coplanarity of the two C3N2-five-membered rings [dihedral angle = 5.64 (10)°]. In the crystal, molecules are linked by N—H⋯N hydrogen bonds, forming a C(8) chain propagating in [001]. The chains are connected by C—H⋯O interactions, generating a three-dimensional network. The previous study [Nagel et al. (1974 ▶). Chem. Commun. pp. 1021–1022] did not establish the absolute structure and no atomic coordinates were published or deposited
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