Self-interaction-corrected Kohn-Sham effective potentials using the density-consistent effective potential method.

Density functional theory (DFT) and beyond-DFT methods are often used in combination with photoelectron spectroscopy to obtain physical insights into the electronic structure of molecules and solids. The Kohn-Sham eigenvalues are not electron removal energies except for the highest occupied orbital. The eigenvalues of the highest occupied molecular orbitals often underestimate the electron removal or ionization energies due to the self-interaction (SI) errors in approximate density functionals. In this work, we adapt and implement the density-consistent effective potential method of Kohut, Ryabinkin, and Staroverov [J. Chem. Phys. 140, 18A535 (2014)] to obtain SI-corrected local effective potentials from the SI-corrected Fermi-Löwdin orbitals and density in the Fermi-Löwdin orbital self-interaction correction scheme. The implementation is used to obtain the density of states (photoelectron spectra) and HOMO-LUMO gaps for a set of molecules and polyacenes. Good agreement with experimental values is obtained compared to a range of SI uncorrected density functional approximations.

Implementation of Perdew-Zunger self-interaction correction in real space using Fermi-Löwdin orbitals.

Most widely used density functional approximations suffer from self-interaction error, which can be corrected using the Perdew-Zunger (PZ) self-interaction correction (SIC). We implement the recently proposed size-extensive formulation of PZ-SIC using Fermi-Löwdin Orbitals (FLOs) in real space, which is amenable to systematic convergence and large-scale parallelization. We verify the new formulation within the generalized Slater scheme by computing atomization energies and ionization potentials of selected molecules and comparing to those obtained by existing FLOSIC implementations in Gaussian based codes. The results show good agreement between the two formulations, with new real-space results somewhat closer to experiment on average for the systems considered. We also obtain the ionization potentials and atomization energies by scaling down the Slater statistical average of SIC potentials. The results show that scaling down the average SIC potential improves both atomization energies and ionization potentials, bringing them closer to experiment. Finally, we verify the present formulation by calculating the barrier heights of chemical reactions in the BH6 dataset, where significant improvements are obtained relative to Gaussian based FLOSIC results.

Study of self-interaction errors in density functional predictions of dipole polarizabilities and ionization energies of water clusters using Perdew-Zunger and locally scaled self-interaction corrected methods.

We studied the effect of self-interaction error (SIE) on the static dipole polarizabilities of water clusters modeled with three increasingly sophisticated, non-empirical density functional approximations (DFAs), viz., the local spin density approximation (LDA), the Perdew-Burke-Ernzerhof (PBE) generalized-gradient approximation (GGA), and the strongly constrained and appropriately normed (SCAN) meta-GGA, using the Perdew-Zunger self-interaction-correction (PZ-SIC) energy functional in the Fermi-Löwdin orbital SIC framework. Our results show that while all three DFAs overestimate the cluster polarizabilities, the description systematically improves from LDA to PBE to SCAN. The self-correlation free SCAN predicts polarizabilities quite accurately with a mean absolute error (MAE) of 0.53 bohr3 with respect to coupled cluster singles and doubles (CCSD) values. Removing SIE using PZ-SIC correctly reduces the DFA polarizabilities, but overcorrects, resulting in underestimated polarizabilities in SIC-LDA, SIC-PBE, and SIC-SCAN. Finally, we applied a recently proposed locally scaled SIC (LSIC) method using a quasi self-consistent scheme and using the kinetic energy density ratio as an iso-orbital indicator. The results show that the LSIC polarizabilities are in excellent agreement with mean absolute errors of 0.08 bohr3 for LSIC-LDA and 0.06 bohr3 for LSIC-PBE with most recent CCSD polarizabilities. Likewise, the ionization energy estimates as absolute of highest occupied energy eigenvalue predicted by LSIC are also in excellent agreement with CCSD(T) ionization energies with MAEs of 0.4 eV for LSIC-LDA and 0.06 eV for LSIC-PBE. The LSIC-LDA predictions of ionization energies are comparable to the reported GW ionization energies, while the LSIC-PBE ionization energies are more accurate than the reported GW results.

Assessing the effect of regularization on the molecular properties predicted by SCAN and self-interaction corrected SCAN meta-GGA.

Recent regularization of the SCAN meta-GGA functional (rSCAN) has simplified the numerical complexities of the SCAN functional, alleviating SCAN's stringent demand on the numerical integration grids to some extent. The regularization of rSCAN, however, results in the breaking of some constraints such as the uniform electron gas limit, the slowly varying density limit, and coordinate scaling of the iso-orbital indicator. Here, we assess the effects of regularization on the electronic, structural, vibrational, and magnetic properties of molecules by comparing the SCAN and rSCAN predictions. The properties studied include atomic energies, atomization energies, ionization potentials, electron affinities, barrier heights, infrared intensities, dissociation and reaction energies, spin moments of molecular magnets, and isomer ordering of water clusters. Our results show that rSCAN requires less dense numerical grids and gives very similar results to those of SCAN for all properties examined with the exception of atomization energies, which are worsened in rSCAN. We also examine the performance of self-interaction-corrected (SIC) rSCAN with respect to SIC-SCAN using the Perdew-Zunger (PZ) SIC method. The PZSIC method uses orbital densities to compute one-electron self-interaction errors and places an even more stringent demand on numerical grids. Our results show that SIC-rSCAN gives marginally better performance than SIC-SCAN for almost all properties studied in this work with numerical grids that are on average half or less as dense as that needed for SIC-SCAN.

A step in the direction of resolving the paradox of Perdew-Zunger self-interaction correction.

Self-interaction (SI) error, which results when exchange-correlation contributions to the total energy are approximated, limits the reliability of many density functional approximations. The Perdew-Zunger SI correction (PZSIC), when applied in conjunction with the local spin density approximation (LSDA), improves the description of many properties, but overall, this improvement is limited. Here, we propose a modification to PZSIC that uses an iso-orbital indicator to identify regions where local SICs should be applied. Using this local-scaling SIC (LSIC) approach with LSDA, we analyze predictions for a wide range of properties including, for atoms, total energies, ionization potentials, and electron affinities and, for molecules, atomization energies, dissociation energy curves, reaction energies, and reaction barrier heights. LSIC preserves the results of PZSIC-LSDA for properties where it is successful and provides dramatic improvements for many of the other properties studied. Atomization energies calculated using LSIC are better than those of the Perdew, Burke, and Ernzerhof generalized gradient approximation (GGA) and close to those obtained with the strongly constrained and appropriately normed meta-GGA. LSIC also restores the uniform gas limit for the exchange energy that is lost in PZSIC-LSDA. Further performance improvements may be obtained by an appropriate combination or modification of the local scaling factor and the particular density functional approximation.

Fermi-Löwdin orbital self-interaction correction using the strongly constrained and appropriately normed meta-GGA functional.

Despite the success of density functional approximations (DFAs) in describing the electronic properties of many-electron systems, the most widely used approximations suffer from self-interaction errors (SIEs) that limit their predictive power. Here, we describe the effects of removing SIE from the strongly constrained and appropriately normed (SCAN) meta-generalized gradient approximation using the Fermi-Löwdin Orbital Self-Interaction Correction (FLOSIC) method. FLOSIC is a size-extensive implementation of the Perdew-Zunger self-interaction correction (PZ-SIC) formalism. We find that FLOSIC-SCAN calculations require careful treatment of numerical details and an integration grid that yields reliable accuracy with this approach. We investigate the performance of FLOSIC-SCAN for predicting a wide array of properties and find that it provides better results than FLOSIC-LDA and FLOSIC-PBE in nearly all cases. It also gives better predictions than SCAN for orbital energies and dissociation energies where self-interaction effects are known to be important, but total energies and atomization energies are made worse. For these properties, we also investigate the use of the self-consistent FLOSIC-SCAN density in the SCAN functional and find that this DFA@FLOSIC-DFA approach yields improved results compared to pure, self-consistent SCAN calculations. Thus, FLOSIC-SCAN provides improved results over the parent SCAN functional in cases where SIEs are dominant, and even when they are not, if the SCAN@FLOSIC-SCAN method is used.

Rehabilitación multidisciplinaria mediante una prótesis obturatríz velopalatal. Reporte de un caso / Multidisciplinary rehabilitation with velopalatal obturator prosthesis: a case report

Se presenta un caso de rehabilitación, en que el paciente sufrió una pérdida de sustancia velopalatal, por resección quirúrgica de un tumor a nivel del velo del paladar (Adenocarcinoma), abordado por el Equipo Multidisciplinario del Servicio de Prótesis Buco Maxilo Facial (S.P.B.M.F.). Se establece un Protocolo de Atención, que incluye: la labor protésica, de la Fonoaudiología y de la Psicología, para la obtención de un tratamiento rehabilitador integral indispensable en estos casos. Se describen distintos procedimientos realizados tales como: etapas clínicas, etapas de laboratorio, registros fonoaudiológicos y entrevistas psicológicas.

A rehabilitation case is presented where the patient suffered a loss of velopalatal tissue following the surgical resection of a soft palate tumor-adenocarcinoma-performed by the multidisciplinary team of the Oral and Maxillofacial Prosthesis Service at the School of Dentistry, Universidad de la República. The care protocol includes the prosthetic rehabilitation and the participation of a speech therapist and a psychologist to provide the comprehensive rehabilitation treatment which is essential in these cases. Different procedures are described, such as clinical stages, laboratory processing, speech therapy records and psychological interviews

Tratamiento conservador en los hematomas intracerebrales supraterritoriales espontáneos / Conservative treatment in the intracranial hematoma supra territorial spontaneous

Se realiza un estudio prospectivo de 50 pacientes diagnosticados por medio de tomografía computarizada craneal (TC) y angiografía carotídea de hematomas intracerebrales espontáneos (HIS) tratados de forma conservadora. Se analizan características clínicas y radiológicas de la fase aguda y la evolución de los pacientes durante el tiempo de ingreso hospitalario. La mortalidad global fue del 32 por ciento. Los factores que influyeron significativamente en el pronóstico fueron: el mayor grado de déficit motor al ingreso, el empeoramiento neural post-ingreso, el mayor volumen del hematoma y la presencia de efecto de masa en los estudios de TC y de angiografía carotídea. Todos los pacientes fueron evaluados clínicamente atendiendo a la escala de Glasgow para el Coma (EGC), con índice de mal pronóstico en todos aquellos que tenían una puntuación igual o inferior a ocho puntos. Se concluye que, de todos los factores evaluados en nuestro estudio, el volumen del hematoma con valor crítico de 50 ml y una puntuación menor de ocho puntos en la EGC son las principales causas en la mala evolución de estos enfermos(AU)

El legrado uterino previo a la histerectomía por Leiomiomatosis uterina / The curetage prior to hysterectomy for Leiomatosis uterine

Si ha sido interés primordial descartar mediante el legrado uterino, la degeneración maligna en la leiomiomatosis u otra patología maligna concomitante, podemos concluir, de acuerdo a los resultados histológicos obtenidos por ese procedimiento, que no se justifica como norma de rutina efectuar el legrado uterino previo a la histerectomía. 2. La biopsia de endometrio, para efectos de iinformación respecto al patrón hormonal, debe de cumplir un requisito elemental que no es otro que efectuarse en la segunda fase del ciclo. Si bien es cierto que en la mayoría de los casos si se tomó en cuenta esta recomendación, lamentablemente en un porcentaje nada despreciable se omitió esta norma, pero debe aclararse que en algunos casos la sintomatología obligó a efectuar el procedimiento sin tomar en cuenta el día del ciclo. 3. En el 17 por ciento de los casos no se obtuvo información, por tratarse de material insuficiente. 4. En cuanto a la poca o nula utilidad terapéutica, es francamente llamativo que en el 96 por ciento de los casos se mantuvieran las mismas condiciones y sólo en el 2 por ciento hubo mejoría temporal. Debemos tener en cuenta que en el 57 por ciento la histerectomía se realizó en un tiempo corto, explicable por persistencia de la sintomatología y por que se había descartado la malignidad.