Fundamental relation between longitudinal and transverse conductivities in the quantum Hall system

We investigate the relation between the diagonal ($\sigma_{xx}$) and off-diagonal ($\sigma_{xy}$) components of the conductivity tensor in the quantum Hall system. We calculate the conductivity components for a short-range impurity potential using the linear response theory, employing an approximation that simply replaces the self-energy by a constant value $-i \hbar /(2 \tau)$ with $\tau$ the scattering time. The approximation is equivalent to assuming that the broadening of a Landau level due to disorder is represented by a Lorentzian with the width $\Gamma = \hbar /(2 \tau)$. Analytic formulas are obtained for both $\sigma_{xx}$ and $\sigma_{xy}$ within the framework of this simple approximation at low temperatures. By examining the leading terms in $\sigma_{xx}$ and $\sigma_{xy}$, we find a proportional relation between $\mathrm{d}\sigma_{xy}/\mathrm{d}B$ and $B \sigma_{xx}^2$. The relation, after slight modification to account for the long-range nature of the impurity potential, is shown to be in quantitative agreement with experimental results obtained in the GaAs/AlGaAs two-dimensional electron system at the low magnetic-field regime where spin splitting is negligibly small.Comment: 21 pages, 8 figures, accepted for publication in J. Phys.: Condens. Matte

Dissociation Potential Curves of Low-Lying States in Transition Metal Hydrides. I. Hydrides of Group 4

The dissociation energy curves of low-lying spin-mixed states for Group 4 hydrides, TiH, ZrH, and HfH, have been calculated using both effective core potential and all-electron approaches. A comprehensive set of theoretical results including the dissociation energies, equilibrium distances, harmonic frequencies, anharmonicities, rotational constants, and dipole moments are reported for these molecules. We present results for both ground and a few excited states, filling a considerable gap in available data for these molecules. Absorption spectra are also predicted on the basis of the results. The present study uses three methods, all based on the multiconfigurational self-consistent field (MCSCF) method, augmented by second-order configuration interaction (SOCI), with either an effective core potential basis set (SBKJC) or a double-ζ basis set (MIDI):  (i) MCSCF+SOCI/SBKJC(f,p) with a one-electron approximation using effective nuclear charges, (ii) MCSCF+SOCI/MIDI(3p,3p) with the full Breit−Pauli Hamiltonian, and (iii) MCSCF +SOCI/MIDI(3p,3p) with the relativistic elimination of the small component scheme and full Breit−Pauli Hamiltonian. The results are compared with previous theoretical studies and available experimental data reported previously. Good agreement is obtained between the results obtained when the first and third methods are used

Dissociation Potential Curves of Low-Lying States in Transition Metal Hydrides. 2. Hydrides of Groups 3 and 5

The dissociation energy curves of low-lying spin-mixed states for Group 5 hydrides (VH, NbH, and TaH), as well as Group 3 hydrides (ScH, YH, and LaH), have been calculated by using both effective core potential (ECP) and all-electron (AE) approaches. The two approaches are based on the multiconfiguration self-consistent field (MCSCF) method, followed by second-order configuration interaction (SOCI) calculations:  the first method employs an ECP basis set proposed by Stevens and co-workers (SBKJC) augmented by a set of polarization functions, and spin−orbit coupling effects are estimated with a one-electron approximation, using effective nuclear charges. The second method employs a double-ζ basis set developed by Huzinaga (MIDI) and three sets of p functions are added to both transition element and hydrogen and one set of f functions is also added to the transition element. The relativistic elimination of small components (RESC) scheme and full Breit−Pauli Hamiltonian are employed in the AE approaches to incorporate relativistic effects. The present paper reports a comprehensive set of theoretical results including the dissociation energies, equilibrium distances, electronic transition energies, harmonic frequencies, anharmonicities, and rotational constants for several low-lying spin-mixed states in the hydrides, filling a considerable gap in available data for these molecules. Transition moments are also computed among the spin-mixed states, and qualitative agreement is obtained for Group 3 hydrides in comparison with the experimental results reported by Ram and Bernath. Peak positions of emission spectra in Group 5 hydrides are also predicted

Patterns of C-reactive protein trends during clozapine titration and the onset of clozapine-induced inflammation: a case series of weekly and daily C-reactive protein monitoring

BackgroundInternational guidelines for clozapine titration recommend measuring C-reactive protein (CRP) weekly for 4 weeks after clozapine initiation to prevent fatal inflammatory adverse events, including myocarditis. However, limited evidence exists regarding whether weekly CRP monitoring can prevent clozapine-induced inflammation.AimsWe examined the relationship between CRP trends and the development of clozapine-induced inflammation. We also explored the usefulness and limitations of CRP monitoring during clozapine titration.MethodThis study presents 17 and 4 cases of weekly and daily CRP monitoring during clozapine initiation, respectively.ResultsAmong 17 patients with weekly CRP measurements, 7 had fever. Elevated CRP levels were detected before the onset of fever in two of the seven patients. Of the five remaining patients, the CRP levels on a previous test had been low; however, the fever developed suddenly. Of the 10 patients with no fever under weekly CRP monitoring, three had elevated CRP levels >3.0 mg/dL. Refraining from increasing the clozapine dose may have prevented fever in these patients. Among four patients with daily CRP measurements, two became febrile. In both cases, CRP levels increased almost simultaneously with the onset of fever.ConclusionWeekly and daily CRP monitoring during clozapine titration is valuable for preventing clozapine-induced inflammation, assessing its severity, and guiding clozapine dose adjustments. Weekly CRP monitoring may not adequately predict clozapine-induced inflammation in some cases. Consequently, clinicians should be aware of the sudden onset of clozapine-induced inflammation, even if CRP levels are low. Daily CRP monitoring is better for detecting clozapine-induced inflammation