Topic Review
Computational Chemistry Methods
The main objective of computational chemistry is to solve chemical problems by simulating chemical systems (molecular, biological, materials) in order to provide reliable, accurate and comprehensive information at an atomic level. To this end, there are two main methodological families: those based on quantum chemical methods and those based on molecular mechanics. The former are methods in which the electrons are explicitly accounted for, while in the latter their presence is hidden in the force field. 
  • 1974
  • 17 Jun 2021
Topic Review
Unmanned Systems
An Unmanned System (US) or Vehicle (UV) can be defined as an “electro-mechanical system, with no human operator aboard, that is able to exert its power to perform designed missions”
  • 1481
  • 17 Mar 2021
Topic Review
Lucas Lamata
Prof. Lucas Lamata is an Associate Professor in Theoretical Physics working at the Department of Atomic, Molecular and Nuclear Physics of Universidad de Sevilla, Spain.
  • 731
  • 23 Mar 2021
Topic Review
Quantum Reinforcement Learning
Quantum machine learning has emerged as a promising paradigm that could accelerate machine learning calculations. Inside this field, quantum reinforcement learning aims at designing and building quantum agents that may exchange information with their environment and adapt to it, with the aim of achieving some goal. Different quantum platforms have been considered for quantum machine learning and specifically for quantum reinforcement learning. Here, we review the field of quantum reinforcement learning and its implementation with quantum platforms. This quantum technology may enhance quantum computation and communication, as well as machine learning, via the fruitful marriage between these previously unrelated fields. 
  • 612
  • 03 Feb 2021
Topic Review
Ionic and Excited Species
Experimental and theoretical studies of either characterization and reactivity of ionic and excited species with atoms, molecules, and radicals of interest in the chemistry of plasmas and energy production. Single and ionized species with single or multiple charge (H+, He+, H3+, HCO+, H3O+, He22+, CO22+, etc.), excited atoms and molecules (e.g. O(1D), N(2D), H*(2s2S1/2), He*(21,3S0,1), N2*(A3Σu+), etc.) play a crucial role in various important chemical systems such as flames (i.e. chemi-ionizations), natural plasmas (i.e. planetary ionospheres, comet tails and interstellar clouds), and biological environments (e.g. damaged biological tissues via the interaction between ionizing radiation and living cells). Such processes are very interesting from a fundamental point of view in Physical Chemistry and attracted the attention of a wide scientific community, since many applications to important fields: radiation chemistry, plasma physics and chemistry, combustion processes, development of laser sources. In particular, the conversion of waste carbon dioxide via assisted plasma technology gained recently increasing interest due to the possibility of obtaining value-added products, like gaseous or liquid fuels. Such characteristics make this an encouraging strategy for the storage of electrical energy from renewable sources into chemical energy in a circular economy scheme.
  • 493
  • 01 Nov 2020
Topic Review
Azulene Moiety as Electron Reservoir
The nonalternant aromatic azulene, an isomer of alternant naphthalene, differs from the latter in peculiar properties. The large polarization of the π-electron system over the seven and five rings gives to azulene electrophile property a pronounced tendency to donate electrons to an acceptor, substituted at azulene 1 position. This paper presents cases in which azulene transfers electrons to a suitable acceptor as methylium ions, positive charged heteroaromatics and examples of neutral molecules that can accept electrons. 
  • 267
  • 18 May 2021
Topic Review
Organic Waste Gasification by Steam and Carbon Dioxide
The selective studies on environmentally friendly, combustion-free, allothermal, atmospheric-pressure, noncatalytic, direct H2O/CO2 gasification of organic feedstocks like biomass, sewage sludge wastes (SSW) and municipal solid wastes (MSW) are considered to demonstrate the pros and cons of the approaches and provide future perspectives. The environmental friendliness of H2O/CO2 gasification is well known as it is accompanied by considerably less harmful emissions into the environment as compared to O2/air gasification. Comparative analysis of the various gasification technologies includes low-temperature H2O/CO2 gasification at temperatures up to 1000 °C, high-temperature plasma- and solar-assisted H2O/CO2 gasification at temperatures above 1200 °C, and an innovative gasification technology applying ultra-superheated steam (USS) with temperatures above 2000 °C obtained by pulsed or continuous gaseous detonations. Analysis shows that in terms of such characteristics as the carbon conversion efficiency (CCE), tar and char content, and the content of harmful by-products the plasma and detonation USS gasification technologies are most promising. However, as compared with plasma gasification, detonation USS gasification does not need enormous electric power with unnecessary and energy-consuming gas–plasma transition.
  • 255
  • 28 Jan 2022
Topic Review
Foams and Emulsions
Foams and emulsions are collections of different kinds of bubbles or drops with particular properties. They provide exceptional sensitive bases for measuring low concentrations of molecules down to the level of traces using spectroscopy techniques, thus opening new horizons in microfluidics. The optical and spectral properties of foams and emulsions provide information about their micro-/nanostructures, chemical and time stability, and molecular data of their components. 
  • 119
  • 19 Apr 2022
Topic Review
Garlic Volatile Diallyl Disulfide
Diallyl disulfide (DADS) is a major allelochemical of the volatile organic compounds in garlic.
  • 117
  • 24 Dec 2021
Topic Review
Valence-shell Electron-pair Repulsion Model
There are the following main assumptions of the Valence-shell Electron-pair Repulsion (VSEPR) model. - The arrangement of covalent bonds of the atom centre analyzed depends on the number of electron pairs in its valence shell: bonds and nonbonding pairs as lone electron pairs. - The arrangement of valence electron pairs around the centre considered is to maximize their distances apart. - The non-valence electrons - inner electrons with nucleus (i.e. the core) possess the spherical symmetry (or at least it is in force for the main groups elements). It is worth to note that the intra- and intermolecular interactions influence on electronic and molecular structures in accordance with this VSEPR model.
  • 101
  • 06 Sep 2021
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