ORCID Profile
0000-0001-9762-7616
Current Organisations
Molecular Sciences Software Institute
,
Virginia Tech
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Publisher: Wiley
Date: 30-06-2021
DOI: 10.1002/QUA.26762
Abstract: The realization of fractional quantum chemistry is presented. Adopting the integro‐differential operators of the calculus of arbitrary‐order, we develop a general framework for the description of quantum nonlocal effects in the complex electronic environments. After a brief overview of the historical and fundamental aspects of the calculus of arbitrary‐order, various classes of fractional Schrödinger equations are discussed and pertinent controversies and open problems around their applications to model systems are detailed. We provide a unified approach toward fractional generalization of the quantum chemical models such as Hartree–Fock and Kohn–Sham density functional theory and develop fractional variants of the fundamental molecular integrals and correlation energy. Furthermore, we offer various strategies for modeling static‐ and dynamic‐order quantum nonlocal effects through constant‐ and variable‐order fractional operators, respectively. Possible directions for future developments of fractional quantum chemistry are also outlined.
Publisher: Springer Science and Business Media LLC
Date: 08-2009
DOI: 10.1038/NATURE08245
Abstract: The 'hot Jupiters' that abound in lists of known extrasolar planets are thought to have formed far from their host stars, but migrate inwards through interactions with the proto-planetary disk from which they were born, or by an alternative mechanism such as planet-planet scattering. The hot Jupiters closest to their parent stars, at orbital distances of only approximately 0.02 astronomical units, have strong tidal interactions, and systems such as OGLE-TR-56 have been suggested as tests of tidal dissipation theory. Here we report the discovery of planet WASP-18b with an orbital period of 0.94 days and a mass of ten Jupiter masses (10 M(Jup)), resulting in a tidal interaction an order of magnitude stronger than that of planet OGLE-TR-56b. Under the assumption that the tidal-dissipation parameter Q of the host star is of the order of 10(6), as measured for Solar System bodies and binary stars and as often applied to extrasolar planets, WASP-18b will be spiralling inwards on a timescale less than a thousandth that of the lifetime of its host star. Therefore either WASP-18 is in a rare, exceptionally short-lived state, or the tidal dissipation in this system (and possibly other hot-Jupiter systems) must be much weaker than in the Solar System.
Publisher: Authorea, Inc.
Date: 16-04-2021
DOI: 10.22541/AU.161856481.14391957/V1
Abstract: The realization of fractional quantum chemistry is presented. Adopting the integro-differential operators of the calculus of arbitrary-order, we develop a general framework for the description of quantum nonlocal effects in the complex electronic environments. After a brief overview of the historical and fundamental aspects of the calculus of arbitrary-order, various classes of fractional Schrödinger equations are discussed and pertinent controversies and open problems around their applications to model systems are detailed. We provide a unified approach toward fractional generalization of the quantum chemical models such as Hartree-Fock and Kohn-Sham density functional theory and develop fractional variants of the fundamental molecular integrals and correlation energy. Furthermore, we offer various strategies for modeling static and dynamic quantum nonlocal effects through constant- and variable-order fractional operators, respectively. Possible directions for future developments of fractional quantum chemistry are also outlined.
Publisher: Unpublished
Date: 2020
Publisher: Zenodo
Date: 2021
Publisher: Springer Science and Business Media LLC
Date: 08-12-2010
DOI: 10.1038/NATURE09602
Abstract: The carbon-to-oxygen ratio (C/O) in a planet provides critical information about its primordial origins and subsequent evolution. A primordial C/O greater than 0.8 causes a carbide-dominated interior, as opposed to the silicate-dominated composition found on Earth the atmosphere can also differ from those in the Solar System. The solar C/O is 0.54 (ref. 3). Here we report an analysis of dayside multi-wavelength photometry of the transiting hot-Jupiter WASP-12b (ref. 6) that reveals C/O ≥ 1 in its atmosphere. The atmosphere is abundant in CO. It is depleted in water vapour and enhanced in methane, each by more than two orders of magnitude compared to a solar-abundance chemical-equilibrium model at the expected temperatures. We also find that the extremely irradiated atmosphere (T > 2,500 K) of WASP-12b lacks a prominent thermal inversion (or stratosphere) and has very efficient day-night energy circulation. The absence of a strong thermal inversion is in stark contrast to theoretical predictions for the most highly irradiated hot-Jupiter atmospheres.
Publisher: World Scientific Pub Co Pte Lt
Date: 31-08-2017
DOI: 10.1142/S0219633617500481
Abstract: We review the fundamental ideas of free complement (FC) method through its application on both ground and first excited states of helium atom. We have found that lower energies can be obtained with fewer number of terms in the FC expansion of the ground state wavefunction. In this case, the optimization of orbital exponents was not necessary for achieving spectroscopic accuracy, especially at higher orders where the structure of the FC wavefunction converges to that of the exact one. We have discovered that permanents naturally appear in the FC expansion of the first triplet excited state wavefunction. Including permanents in the FC expansion is shown to be energetically important for the first triplet excited state of helium atom whereas it is not computationally favorable at higher orders. Finally, considering the group theoretical properties of the symmetric group [Formula: see text] and using immanants, a compact and more elegant form for the FC expansion of the first triplet excited state of the helium atom is achieved.
Publisher: Elsevier BV
Date: 11-2012
Publisher: Authorea, Inc.
Date: 20-04-2022
DOI: 10.22541/AU.164910777.74730983/V2
Abstract: The An error in the conversion from LaTeX to XML has occurred here. MolSSI is a research and education center that supports software development in the An error in the conversion from LaTeX to XML has occurred here. CMS. One of An error in the conversion from LaTeX to XML has occurred here. MolSSI’s core objectives is to provide education and training for the next generation of computational researchers. An error in the conversion from LaTeX to XML has occurred here. MolSSI Education targets various career stages and skill levels through its live workshops, online resources, and software fellowship program. An error in the conversion from LaTeX to XML has occurred here. MolSSI Education focuses its efforts within four areas: programming and software development, An error in the conversion from LaTeX to XML has occurred here. HPC and An error in the conversion from LaTeX to XML has occurred here. AI, faculty and curriculum development, and the An error in the conversion from LaTeX to XML has occurred here. MolSSI software fellowship program. This article delineates educational efforts at the An error in the conversion from LaTeX to XML has occurred here. MolSSI, overall goals, and resources that can be useful to researchers in the computational molecular sciences.
Publisher: Authorea, Inc.
Date: 04-04-2022
DOI: 10.22541/AU.164910777.74730983/V1
Abstract: The An error in the conversion from LaTeX to XML has occurred here. MolSSI is a research and education center that supports software development in the An error in the conversion from LaTeX to XML has occurred here. CMS. One of An error in the conversion from LaTeX to XML has occurred here. MolSSI’s core objectives is to provide education and training for the next generation of computational researchers. An error in the conversion from LaTeX to XML has occurred here. MolSSI Education targets various career stages and skill levels through its live workshops, online resources, and software fellowship program. An error in the conversion from LaTeX to XML has occurred here. MolSSI Education focuses its efforts within four areas: programming and software development, An error in the conversion from LaTeX to XML has occurred here. HPC and An error in the conversion from LaTeX to XML has occurred here. AI, faculty and curriculum development, and the An error in the conversion from LaTeX to XML has occurred here. MolSSI software fellowship program. This article delineates educational efforts at the An error in the conversion from LaTeX to XML has occurred here. MolSSI, overall goals, and resources that can be useful to researchers in the computational molecular sciences.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-2022
Publisher: Unpublished
Date: 2017
Publisher: American Chemical Society (ACS)
Date: 26-02-2020
Publisher: Wiley
Date: 19-06-2014
DOI: 10.1002/QUA.24721
Publisher: American Chemical Society (ACS)
Date: 26-07-2019
DOI: 10.26434/CHEMRXIV.9108527.V1
Abstract: We present a heterogeneous CPU+GPU algorithm for the direct variational optimization of the two-electron reduced-density matrix (2RDM) under two-particle N-representability conditions. This variational 2RDM (v2RDM) approach is the driver for a polynomially-scaling approximation to configuration-interaction-driven complete active space self-consistent field (CASSCF) theory. For v2RDM-based CASSCF com- putations involving an active space consisting of 50 electrons in 50 orbitals [denoted (50e,50o)], we observe a speedup of a factor of 3.7 when the code is executed on a combination of an NVIDIA TITAN V GPU and an Intel Core i7-6850k CPU, relative to the case when the code is executed on the CPU alone. We use this GPU-accelerated v2RDM-CASSCF algorithm to explore the electronic structure of the 3,k-circumacene and 3,k-periacene series (k=2–7) and compare indicators of polyradical character in the lowest-energy singlet states to those observed for oligoacene molecules. The singlet states in larger circumacene and periacene molecules display the same polyradical characteristics observed in oligoacenes, with the onset of this behavior occuring at smallest k for periacenes, followed by the circumacenes and then the oligoacenes. However, the unpaired electron density that accumulates along the zig-zag edge of the circumacenes is slightly less than that which accumulates in the oligoacenes, while periacenes clearly exhibit the greatest build-up of unpaired electron density in this region.
Publisher: American Chemical Society (ACS)
Date: 17-12-2018
Abstract: Complete active space self-consistent field (CASSCF) computations can be realized at polynomial cost via the variational optimization of the active-space two-electron reduced-density matrix (2-RDM). Like conventional approaches to CASSCF, variational 2-RDM (v2RDM) driven CASSCF captures nondynamical electron correlation in the active space, but it lacks a description of the remaining dynamical correlation effects. Such effects can be modeled through a combination of v2RDM-CASSCF and on-top pair-density functional theory (PDFT). The resulting v2RDM-CASSCF-PDFT approach provides a computationally inexpensive framework for describing both static and dynamical correlation effects in multiconfigurational and strongly correlated systems. On-top pair-density functionals can be derived from familiar Kohn-Sham exchange-correlation (XC) density functionals through the translation of the v2RDM-CASSCF reference densities [ Li Manni et al. J. Chem. Theory Comput. 2014 , 10 , 3669 - 3680 ]. Translated and fully translated on-top PDFT versions of several common XC functionals are applied to the potential energy curves of N
Publisher: American Chemical Society (ACS)
Date: 25-09-2019
Abstract: We present a heterogeneous central processing unit (CPU) + graphical processing unit (GPU) algorithm for the direct variational optimization of the two-electron reduced-density matrix (2RDM) under two-particle
Publisher: Royal Society of Chemistry (RSC)
Date: 2019
DOI: 10.1039/C9CP04595C
Abstract: We present a basis-independent metric to assess the quality of the electron density obtained from Kohn–Sham (KS) density functional theory (DFT).
Location: United States of America
No related grants have been discovered for Mohammad Mostafanejad.