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29 results on '"Maçôas, Ermelinda M. S."'

1. Safety assessment of new nanodiamonds@corrole hybrids addressed by the response of RAW-264.7 macrophages

Author

Santos, Carla I. M., primary, Cicuéndez, Mónica, additional, Gonçalves, Gil, additional, Rodríguez-Pérez, Laura, additional, Portolés, M. Teresa, additional, Faustino, M. Amparo F., additional, Herranz, M. Ángeles, additional, Neves, M. Graça P. M. S., additional, Martinho, José M. G., additional, Maçôas, Ermelinda M. S., additional, and Martín, Nazario, additional

Published
2023
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2. Enhanced Photodynamic Therapy Effects of Graphene Quantum Dots Conjugated with Aminoporphyrins

Author

Santos, Carla I. M., primary, Rodríguez-Pérez, Laura, additional, Gonçalves, Gil, additional, Dias, Cristina J., additional, Monteiro, Fátima, additional, Faustino, Maria do Amparo F., additional, Vieira, Sandra I., additional, Helguero, Luisa A., additional, Herranz, María Ángeles, additional, Martín, Nazario, additional, Neves, M. Graça P. M. S., additional, Martinho, José M. G., additional, and Maçôas, Ermelinda M. S., additional

Published
2021
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18. Role of Vibrational Dynamics in Electronic Relaxationof Cr(acac)3.

Author

Maçôas, Ermelinda M. S., Mustalahti, Satu, Myllyperkiö, Pasi, Kunttu, Henrik, and Pettersson, Mika

Subjects
*RELAXATION phenomena, *VINYL chloride, *VIBRATIONAL redistribution (Molecular physics), *CHROMIUM compounds, *TIME-resolved spectroscopy, *INFRARED spectroscopy
Abstract

Ultrafastenergy relaxation of Cr(acac)3dissolved intetrachloroethylene (TCE) is studied by time-resolved infrared (TRIR)spectroscopy by using electronic and vibrational excitation. Afterelectronic excitation at 400 or 345 nm, the ground state recoversin two time scales: 15 ps (major pathway) and 800 ps (minor pathway),corresponding to fast electronic transition to the ground state andintermediate trapping on the long-lived 2E state followedby intersystem crossing (ISC) to the ground state. The quantum yieldfor the fast recovery of the ground state depends on the excitationwavelength, being higher for 345 nm. Vibrational cooling (VC) occurson the electronic excited states with a time constant of ∼7ps and on the ground electronic state with a time constant of ∼12ps. A kinetic model that explains the observed dynamics is presented.The key point of the model is that the ground-state recovery occursvia thermally activated back-intersystem-crossing (b-ISC) to the quartetmanifold presumably via multiple curve crossings that are sampledwhile the system is vibrationally hot. This underlines the importanceof vibrational cooling as a determining factor for the electronicrelaxation chain. Vibrational excitation of the νCCand νCO vibrations also revealed a subpicosecond (300–700fs) intramolecular vibrational redistribution (IVR) process from thelocalized vibrational states to the bath of vibrational excitations. [ABSTRACT FROM AUTHOR]

Published
2015
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28. Relaxation Dynamics of Cr(acac)3 Probed by Ultrafast Infrared Spectroscopy.

Author

Maçôas, Ermelinda M. S., Kananavicius, Robertas, Myllyperkia, Pasi, Pettersson, Mika, and Kunttu, Henrik

Subjects
*CHROMIUM compounds, *MOLECULAR dynamics, *INFRARED spectroscopy, *INORGANIC compounds, *PHYSICS
Abstract

The article describes the dynamics of Cr(acac)3 (acac = deprotonated monoanion of acetylacetone) by ultrafast infrared (IR) spectroscopy. According to the authors, the study shows the great value of transient IR spectroscopy in inorganic photophysics. They add the results suggest that most of the ground state population of Cr(acac)3 recovers with a time constant of 15 ps and the rest follows the lifetime of the ²E state.

Published
2007
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