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Orientation of Chiral Molecules by External Electric Fields: Focus on Photodissociation Dynamics. Symmetry (Basel) 2022. [DOI: 10.3390/sym14102152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Molecular orientation is a fundamental requirement to study and control photoinitiated reactions. Experimental setups that make use of hexapolar electric filters combined with slice-ion imaging detectors were employed in these last years to investigate the photodissociation dynamics of chiral molecules. The final goal is the on-the-fly discrimination of oriented enantiomers, revealed by the different angular distributions in photofragment ion-imaging, as predicted from vector correlation studies. Here, we review experiments of photodissociation of oriented chiral molecules, with the aim of presenting limits emerging from these investigations and perspectives toward the achievement of the ultimate objective.
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The role of primordial atmosphere composition in organic matter delivery to early Earth. RENDICONTI LINCEI. SCIENZE FISICHE E NATURALI 2020. [DOI: 10.1007/s12210-020-00878-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Machado HG, Sanches-Neto FO, Coutinho ND, Mundim KC, Palazzetti F, Carvalho-Silva VH. "Transitivity": A Code for Computing Kinetic and Related Parameters in Chemical Transformations and Transport Phenomena. Molecules 2019; 24:E3478. [PMID: 31557893 PMCID: PMC6803931 DOI: 10.3390/molecules24193478] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 09/04/2019] [Accepted: 09/08/2019] [Indexed: 12/25/2022] Open
Abstract
The Transitivity function, defined in terms of the reciprocal of the apparent activation energy, measures the propensity for a reaction to proceed and can provide a tool for implementing phenomenological kinetic models. Applications to systems which deviate from the Arrhenius law at low temperature encouraged the development of a user-friendly graphical interface for estimating the kinetic and thermodynamic parameters of physical and chemical processes. Here, we document the Transitivity code, written in Python, a free open-source code compatible with Windows, Linux and macOS platforms. Procedures are made available to evaluate the phenomenology of the temperature dependence of rate constants for processes from the Arrhenius and Transitivity plots. Reaction rate constants can be calculated by the traditional Transition-State Theory using a set of one-dimensional tunneling corrections (Bell (1935), Bell (1958), Skodje and Truhlar and, in particular, the deformed ( d -TST) approach). To account for the solvent effect on reaction rate constant, implementation is given of the Kramers and of Collins-Kimball formulations. An input file generator is provided to run various molecular dynamics approaches in CPMD code. Examples are worked out and made available for testing. The novelty of this code is its general scope and particular exploit of d -formulations to cope with non-Arrhenius behavior at low temperatures, a topic which is the focus of recent intense investigations. We expect that this code serves as a quick and practical tool for data documentation from electronic structure calculations: It presents a very intuitive graphical interface which we believe to provide an excellent working tool for researchers and as courseware to teach statistical thermodynamics, thermochemistry, kinetics, and related areas.
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Affiliation(s)
- Hugo G Machado
- Grupo de Química Teórica e Estrutural de Anápolis, Centro de Pesquisa e Pós-Graduação. Universidade Estadual de Goiás, 75132-400 Anápolis, GO, Brazil.
- Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970 Brasília, Brazil.
| | - Flávio O Sanches-Neto
- Grupo de Química Teórica e Estrutural de Anápolis, Centro de Pesquisa e Pós-Graduação. Universidade Estadual de Goiás, 75132-400 Anápolis, GO, Brazil.
- Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970 Brasília, Brazil.
| | - Nayara D Coutinho
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, 06123 Perugia, Italy.
| | - Kleber C Mundim
- Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970 Brasília, Brazil.
| | - Federico Palazzetti
- Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, 06123 Perugia, Italy.
| | - Valter H Carvalho-Silva
- Grupo de Química Teórica e Estrutural de Anápolis, Centro de Pesquisa e Pós-Graduação. Universidade Estadual de Goiás, 75132-400 Anápolis, GO, Brazil.
- Instituto de Química, Universidade de Brasília, Caixa Postal 4478, 70904-970 Brasília, Brazil.
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