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Quantum Chemical Investigation (quantum + chemical_investigation)
Selected AbstractsAb Initio Quantum Chemical Investigation of the First Steps of the Photocycle of Phototropin: A Model Study,PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2003Christian Neiß ABSTRACT Phototropin is a blue light,activated photoreceptor that plays a dominant role in the phototropism of plants. The protein contains two subunits that bind flavin mononucleotide (FMN), which are responsible for the initial steps of the light-induced reaction. It has been proposed that the photoexcited flavin molecule adds a cysteine residue of the protein backbone, thus activating autophosphorylation of the enzyme. In this study, the electronic properties of several FMN-related compounds in different charge and spin states are characterized by means of ab initio quantum mechanical calculations. The model compounds serve as idealized model chromophores for phototropism. Reaction energies are estimated for simple model reactions, roughly representing the addition of a cysteine residue to the flavin molecule. Excitation energies were calculated with the help of time-dependent density functional theory. On the basis of these calculations we propose the following mechanism for the addition reaction: (1) after photoexcitation of FMN out of the singlet ground state S0, excited singlet state(s) are populated; these relax to the lowest excited singlet state S1, and subsequently by intersystem crossing FMN in the lowest triplet state, T1 is formed; (2) the triplet easily removes the neutral hydrogen atom from the H,S group of the cysteine residue; and (3) the resulting thio radical is added. [source] ChemInform Abstract: Interaction of Trivalent Lanthanide Cations with Nitrate Anions: A Quantum Chemical Investigation of Monodentate/Bidentate Binding Modes.CHEMINFORM, Issue 3 2002Marc Dobler Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Structures, Energetics, and Vibrational Spectra of H2O2××× (H2O)n, n = 1,6 Clusters: Ab initio Quantum Chemical Investigations.CHEMINFORM, Issue 35 2005Anant D. Kulkarni No abstract is available for this article. [source] TmoleX,A graphical user interface for TURBOMOLEJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 16 2010Claudia Steffen Abstract We herein present the graphical user interface (GUI) TmoleX for the quantum chemical program package TURBOMOLE. TmoleX allows users to execute the complete workflow of a quantum chemical investigation from the initial building of a structure to the visualization of the results in a user friendly graphical front end. The purpose of TmoleX is to make TURBOMOLE easy to use and to provide a high degree of flexibility. Hence, it should be a valuable tool for most users from beginners to experts. The program is developed in Java and runs on Linux, Windows, and Mac platforms. It can be used to run calculations on local desktops as well as on remote computers. © 2010 Wiley Periodicals, Inc. J Comput Chem 2010 [source] | ||||||||||