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UC.PT

Theoretical & Computational Chemistry

Luís Pedro Viegas

Academic background

Finished undergraduate studies in Chemistry in 2002  and PhD in Theoretical Chemistry under the supervision of Professor António Varandas in 2008, both in University of Coimbra. Currently a Post-doctoral fellow in the T&CC Group.

Areas of interest

My current interests concern green chemistry, namely theoretical studies of atmospheric reactions with environmental impact based on ab initio and DFT calculations. Ongoing work is two-fold: influence of water clusters in the HO2+O3 reaction and degradation and kinetics of a promising new class of hydrofluoropolyethers (this new class of HFPEs is recent and there is practically no existing data related to its environmental chemistry), which are planned to used as substitutes of hazardous CFCs and related compounds in a wide variety of applications and therefore planned to released into the troposphere. 

During my PhD my research was focused on vibrational spectroscopy studies including the geometric phase effect based on potential energy surfaces for H3+ (singlet and triplet) constructed within the DMBE formalism.

Publications:


"Mapping the HO3 ground state potential energy surface with DFT: Can we reproduce the MRCI+Q/CBS data?" L. P. Viegas, D. Carolina and A. J. C. Varandas, Chem. Phys. Lett. 620, 61 (2015) http://dx.doi.org/10.1016/j.cplett.2014.12.034

"Coupled-cluster reaction barriers of HO2+H2O+O3: an application of the coupled-cluster//Kohn-Sham density functional theory model chemistry" L. P. Viegas and A. J. C. Varandas, J. Comput. Chem. 35, 507 (2014) http://dx.doi.org/10.1002/jcc.23458

"A detailed test study of barrier heights for the HO2+H2O+O3 reaction with various forms of multireference perturbation theory" L. P. Viegas and A. J. C. Varandas, J. Chem. Phys. 136, 114312 (2012) http://dx.doi.org/10.1063/1.3695371

"Can water be a catalyst on the HO2+H2O+O3 reactive cluster?” L. P. Viegas and A. J. C. Varandas, Chem. Phys. 399, 17 (2011) http://dx.doi.org/10.1016/j.chemphys.2011.04.022

”The HO2+O3 reaction: Current status and prospective work” A. J. C. Varandas and L. P. Viegas, Comput. Theoret. Chem. 965, 291 (2011) http://dx.doi.org/10.1016/j.comptc.2010.09.010

”How well can Kohn-Sham DFT describe the HO2+O3 reaction?” L. P. Viegas, Adriana Branco and A. J. C. Varandas, J. Chem. Theory Comput. 6, 2751 (2010) http://dx.doi.org/10.1021/ct100364x

”The HO2+O3 reaction: ab initio study and implications in atmospheric chemistry” L. P. Viegas and A. J. C. Varandas, J. Chem. Theory Comput. 6, 412 (2010) http://dx.doi.org/10.1021/ct900370q

”Geometric phase effect in the vibrational states of triplet H3+” L. P. Viegas and A. J. C. Varandas, Phys. Rev. A 77, 032505 (2008) http://dx.doi.org/10.1103/PhysRevA.77.032505

“Accurate ab initio based multisheeted double many-body expansion potential energy surface for the three lowest electronic singlet states of H3+” L. P. Viegas, A. Alijah and A. J. C. Varandas, J. Chem. Phys. 126, 074309 (2007) http://dx.doi.org/10.1063/1.2566770

“Symmetry analysis of the vibronic states in the upper conical potential (2 3A') of triplet H3+” L. P. Viegas, A. Alijah and A. J. C. Varandas, J. Phys. Chem. A 109, 3307 (2005) http://dx.doi.org/10.1021/jp0448301

“H3+ in the electronic triplet state” A. J. C. Varandas, A. Alijah, M. Cernei and L. P. Viegas in: Quantum Dynamics at Conical Intersections, CCP6 (Collaborative Computational Project No. 6) Research Monographs, U.K., 31-37 (2004) http://www.ccp6.ac.uk/booklets/CCP6-2004_qdyn_conicint.pdf

 “Accurate double many-body expansion potential energy surface for triplet H3+. II. The upper adiabatic sheet (2 3A')” L. P. Viegas, M. Cernei, A. Alijah and A. J. C. Varandas, J. Chem. Phys. 120, 253 (2004) http://dx.doi.org/10.1063/1.1630023

 “Ro-vibrational states of triplet H3+: The lowest 19 bands” A. Alijah, L. P. Viegas, M. Cernei and A. J. C. Varandas, J. Mol. Spectrosc. 221, 163 (2003) http://dx.doi.org/10.1016/S0022-2852(03)00229-7

“Cone states of tri-hydrogen isotopomers and criterion for the geometric phase effect” A. J. C. Varandas and L. P. Viegas, Chem. Phys. Lett. 367, 625 (2003) http://dx.doi.org/10.1016/S0009-2614(02)01780-3