Traveling wave enantioselective electron paramagnetic resonance

Producción CientíficaWe propose a novel method for enantioselective electron paramagnetic resonance (EPR) spectroscopy based on magneto-chiral anisotropy. We elaborate a theoretical model to estimate the strength of this effect and propose a dedicated interferometer setup for its experimental observation.Agence Nationale de la Recherche (SECRETS, (ANR PRC 20-CE06-0023-01)Laboratory of Excellence NanoX (ANR-17-EURE-0009

A complex-polarization-propagator protocol for magneto-chiral axial dichroism and birefringence dispersion

A computational protocol for magneto-chiral dichroism and magneto-chiral birefringence dispersion is presented within the framework of damped response theory, also known as complex polarization propagator theory, at the level of time-dependent Hartree\u2013Fock and time-dependent density functional theory. Magneto-chiral dichroism and magneto-chiral birefringence spectra in the (resonant) frequency region below the first ionization threshold of R-methyloxirane and L-alanine are presented and compared with the corresponding results obtained for both the electronic circular dichroism and the magnetic circular dichroism. The additional information content yielded by the magneto-chiral phenomena, as well as their potential experimental detectability for the selected species, is discussed

Negative experimental evidence for magneto-orbital dichroism - supplemental information

A light beam can carry both spin angular momentum (SAM) and orbital angular momentum (OAM). SAM is commonly evidenced by circular dichroism (CD) experiments {\em i. e.} differential absorption of left and right-handed circularly polarized light. Recent experiments, supported by theoretical work, indicate that the corresponding effect with OAM instead of SAM is not observed in chiral matter. Isotropic materials can show CD when subjected to a magnetic field (MCD). In Ref. ~\onlinecite{Mathevet2012} we report a set of experiments, under well defined conditions, searching for magnetic orbital dichroism (MOD), differential absorption of light as a function of the sign of its OAM. We experimentally demonstrate that this effect, if any, is smaller than a few $10^{-4}$ of MCD for the Nd:YAG $^4I_{9/2}\rightarrow^4F_{5/2}$ transition. This transition is essentially of electric dipole nature. We give an intuitive argument suggesting that the lowest order of light matter interaction leading to MOD is the electric quadrupole term. We give here more experimental details and extra measurements.Comment: 6 pages, 7 figures. Supplemental material for a publication in Optics Expres

The Diamagnetic Susceptibility of the Tubulin Dimer

An approximate value of the diamagnetic anisotropy of the tubulin dimer, Δχdimer, has been determined assuming axial symmetry and that only the α-helices and β-sheets contribute to the anisotropy. Two approaches have been utilized: (a) using the value for the Δχα for an α-helical peptide bond given by Pauling (1979) and (b) using the previously determined anisotropy of fibrinogen as a calibration standard. The Δχdimer≈4×10-27 JT−2 obtained from these measurements are similar to within 20%. Although Cotton-Mouton measurements alone cannot be used to estimate Δχ directly, the value we measured, CMdimer=1.41±0.03×10-8 T−2cm2mg−1, is consistent with the above estimate for Δχdimer. The method utilized for the determination of the tubulin dimer diamagnetic susceptibility is applicable to other proteins and macromolecular assemblies as well