arXiv subjects

Brian Toby

Publications and source records attributed to Brian Toby.

3 recordsLinked to original sources

arXiv2015

RIXS and excited states calculation with the Xclaim code

We discuss the calculation of resonant inelastic x-ray scattering (RIXS) with Xclaim, a multi-plaform code for the calculation of core-hole spectroscopy based on a ligand-field multiplet model. RIXS can be calcuated with a ligand-field model with ligands for the L$_{2,3}$, M$_{2,3}$, $K_{\alpha}$ and $K_{\beta}$ edges for $d$-valence metals. In addition, the program brings the possibility of fully diagonalizing the hamiltonian to classify the excited states. The command line use of xclaim is described for scripting purposes to help in automatizing the results that can be obtained with the graphical interface.

cond-mat.str-el↗

arXiv2014

Xclaim: a graphical interface for the calculation of core-hole spectroscopies

Xclaim (x-ray core level atomic multiplets) is a graphical interface for the calculation of core-hole spectroscopy and ground state properties within a charge-transfer multiplet model taking into account a many-body hamiltonian with Coulomb, spin-orbit, crystal-field, and hybridization interactions. Using Hartree-Fock estimates for the Coulomb and spin-orbit interactions and ligand field parameters (crystal-field, hybridization and charge-transfer energy) the program can calculate x-ray absorption spectroscopy (XAS), x-ray photoemission spectroscopy (XPS), photoemission spectrospcy (PES) and inverse photoemission (IPES) for d- and f-valence metals and different absorption edges. The program runs in Linux, Windows and MacOS platforms.

cond-mat.str-el↗

arXiv2014

Mixed configuration ground state in Iron(II) Phthalocyanine

We calculate the angular dependence of the x-ray linear and circular dichroism at the $L_{2,3}$ edges of $\alpha$-Fe(II) Phthalocyanine (FePc) thin films using a ligand field model with full configuration interaction. We find the best agreement with the experimental spectra for a mixed ground state of $^3E_{g}(a_{1g}^2e_g^3b_{2g}^1)$ and $^3B_{2g}(a_{1g}^1e_g^4b_{2g}^1)$ with the two configurations coupled by the spin-orbit interaction. The $^3E_{g}(b)$ and $^3B_{2g}$ states have an easy axis and plane anisotropies, respectively. Our model accounts for an easy-plane magnetic anisotropy and the measured magnitudes of the in-plane orbital and spin moments. The proximity in energy of the two configurations allows a switching of the magnetic anisotropy from easy plane to easy axis with a small change in the crystal field, as recently observed for FePc adsorbed on an oxidized Cu surface. We also discuss the possibility of a quintet ground state ($^5A_{1g}$ is 250~meV above the ground state) with planar anisotropy by manipulation of the Fe-C bond length by depositing the complex on a substrate that is subjected to a mechanical strain.

cond-mat.str-el↗