Carlos E V de Moura

• PhD
• Postdoctoral Associate at University of Florida

PyCI is a free and open-source Python library for setting up and running arbitrary determinant-driven configuration interaction (CI) computations, as well as their generalizations to cases where the coefficients of the determinant are nonlinear functions of optimizable parameters. PyCI also includes functionality for computing the residual correlat...

Accurate simulations of transient X-ray photoelectron spectra (XPS) provide unique opportunities to bridge the gap between theory and experiment in understanding the photoactivated dynamics in molecules and materials. However, simulating...

We studied N 1s-1 inner-shell processes of the free base Phthalocyanine molecule, H2Pc, in the gas-phase. This complex organic molecule contains three different nitrogen sites defined by their covalent bonds. We identify the contribution of each site in ionized, core-shell excited or relaxed electronic states by the use of different theoretical met...

A comparison of four approaches to account the vibronic coupling in photoabsorption is performed. The methods considered are nuclear ensemble (NE), direct vibronic coupling (DVC), adiabatic Hessian (AH), and vertical gradient (VG). The case study is the symmetry-forbidden 𝑋̃ 1A1 → 𝐴̃ 1A2 (n → 𝜋∗) transition in formaldehyde. Being forbidden in the e...

We propose a novel approach for an indirect probing of conjugation and hyperconjugation in core-excited molecules using resonant Auger spectroscopy. Our work demonstrates that the changes in the electronic structure of thiophene (C4H4S) and thiazole (C3H3NS), occurring in the process of resonant sulfur K-shell excitation and Auger decay, affect the...

Correction for 'Simulating X-ray photoelectron spectra with strong electron correlation using multireference algebraic diagrammatic construction theory' by Carlos E. V. de Moura and Alexander Yu. Sokolov, Phys. Chem. Chem. Phys., 2022, 24, 4769-4784, DOI: 10.1039/D1CP05476G.

We present a new theoretical approach for the simulations of X-ray photoelectron spectra of strongly correlated molecular systems that combines multireference algebraic diagrammatic construction theory (MR-ADC) [J. Chem. Phys., 2018, 149, 204113] with core-valence separation (CVS) technique. The resulting CVS-MR-ADC approach has a low computational...

A recent experimental study with time-resolved velocity map imaging demonstrated that the total kinetic energy release spectra obtained from photodissociation of ortho and meta fluorophenols have distinct features after excitation into the origin of the S₁ state. A peak at 6000 cm^-1 was observed for both molecules, while anoth...

We present a systematic study of high-resolution NEXAFS spectra of well-ordered films of condensed benzene and polyacenes, namely naphthalene, anthracene, tetracene, and pentacene. An increased spectral complexity with increasing molecular size is observed: NEXAFS features decrease in intensity and moves to lower photon energy(redshift), as the siz...

Transitions energies, optical oscillator strengths and partial potential energy surfaces of inner-shell (core–hole) states of water clusters are calculated at the inner-shell multiconfigurational self-consistent field (IS-MCSCF) level. This approach has been applied to diatomic and small polyatomic molecules with high accuracy. In the present work,...

The role of additives and thermal treatment in the formation of donor–acceptor copolymer organic films of PFO–DBT (poly[2,7-(9,9-dioctylfluorene)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole]) with increased transport properties is addressed by resonant Auger photoemission and core-hole clock spectroscopy, which allows an analysis of the compe...

In order to study the stability of the disulfide chemical bond in molecules subjected to a flux of high energy photons, the ionic fragmentation of two molecules containing a disulfide chemical bond, dimethyl disulfide (DMDS) and methyl propyl disulfide (MPDS), has been studied following excitation around the S 1s edge (∼2470 eV). Synchrotron radiat...

Polythiophene and its derivatives have been promising semiconducting polymers for organic optoelectronic devices. Some of their properties, like formation of thin films with good optical properties, low band gap and higher stability, are advantageous to this kind of application. In previous works, we studied PFO-DBT copolymer at point of view of in...

We have performed X-ray Photoelectron Spectroscopy (XPS) and [Formula presented] Near-Edge X-ray Absorption Fine Structure (NEXAFS) spectroscopy on PSiF-DBT:PC71BM, which is a low bandgap polymer blended with a C70 fullerene derivative, aiming at understanding the change in electronic and structural properties caused by thermal annealing, since the...

Plant volatiles are emitted by plants in response to several forms of stress, including interaction with energetic photons. In the present work, we discuss the interaction of extreme UV and soft X-rayphotons with a plant volatile, vanillin. The single and double (multiple) ionization of the vanillin molecule have been studied for the first time usi...

Organic optoelectronic devices constitute an important class of materials, which can be applied in renewable sources of energy. The fundamental physical process is the charge transfer dynamics of an exciton generated after solar radiation absorption. In this work, the structure of thin-films of PFO-DBT and PSiF-DBT are studied by means of inner-she...

Ultrafast charge delocalization dynamics in excited states of internal donoracceptor copolymer poly[2,7-(9,9-bis(2-ethylhexyl)-dibenzosilole)-alt-4,7-bis(thiophen-2-yl)benzo-2,1,3-thiadiazole] (PSiF-DBT) was studied by resonant Auger spectroscopy (RAS) measured around silicon and sulfur K edges using the core-hole clock approach. The effect of the...

Estados eletrônicos excitados de camada interna têm sido cada vez mais aplicados no estudo da natureza de sistemas químicos. O comportamento deste tipo de estado é característico de cada elemento, ainda que sejam sensíveis ao ambiente químico no qual o mesmo se encontra. Mudanças na estrutura fina deste tipo de espectro se manifestam através dos de...

Potential energy curves and inner-shell ionization energies of carbon monoxide, oxygen and nitrogen molecules were calculated using several forms of the inner-shell multiconfigurational self-consistent field (IS-MCSCF) method-a recently proposed protocol to obtain specifically converged inner-shell states at this level. The particular forms of the...

Potential energy curves for inner-shell states of nitrogen and carbon dioxide molecules are calculated by inner-shell complete active space self-consistent field (CASSCF) method, which is a protocol, recently proposed, to obtain specifically converged inner-shell states at multiconfigurational level. This is possible since the collapse of the wave...