ORCID Profile
0000-0003-1868-5004
Current Organisation
Columbia University
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Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-16683
Abstract: Global geochemical datasets are increasingly valuable for solving research questions in geochemistry, volcanology and beyond. To support new research, open sharing and access of geochemical data needs to be easy for researchers so they can take full advantage of the rapidly growing volume of data generated in laboratories across the globe, and to comply with the principles of Open Science. Instead, the fragmented landscape of geochemical data systems makes it difficult for researchers to find, access, and contribute their data: Geochemical data are curated and published in a range of thematic, institutional, and programmatic data systems that differ in architecture, metadata schemas, terminology, and data output formats. Researchers have to figure out where to obtain the data they need learn to use different search applications retrieve data from multiple databases and painstakingly reformat the datasets they obtained from different systems to integrate them. They need to select an appropriate repository for their data, and potentially work with different submission systems and templates. Collaboration among geochemical data systems is a critical step to overcome this fragmentation and facilitate geochemical data management and access for the research community by coordinating, aligning, and integrating their systems. Through collaboration, data repositories and databases can also leverage each other& #8217 s expertise and resources to operate their services more effectively and efficiently.We here report about new collaborative efforts among four geochemical data systems that aim to harmonize and integrate their data holdings and software ecosystem for the benefit of the research community and to improve their sustainability: EarthChem (earthchem.org/), GEOROC (georoc.eu/), MetBase (metbase.org/), and the Astromaterials Data System (www.astromat.org/).& Building on the long-term collaboration between EarthChem and GEOROC, this collaboration leverages the new development of the Astromaterials Data System with modern technology and two new projects funded to overhaul the infrastructure of the GEOROC and MetBase databases as an opportunity to jointly develop a more resilient, sustainable platform for data exchange. Results of the collaboration so far include: a) alignment of the Astronaut and MetBase data models b) migration of the MetBase data holdings into the Astromat synthesis database c) alignment of the EarthChem and GEOROC data models d) new automated synchronization process of GEOROC data to the ECP e) harmonized vocabularies for chemical variables, analytical methods (Others are in development in alignment with emerging efforts of the OneGeochemstry initiative) f) design of the future shared architecture of EarthChem and GEOROC that includes plans for a joint data entry tool for curators and a single data submission platform for researchers to contribute their data to the affiliated domain repositories.& The ultimate goal of this harmonization between EarthChem, Astromat, GEOROC and MetBase is to make it easier for researchers to access and contribute data. We& hope to integrate further systems in the future, building on ongoing collaborations with the Australian Geochemistry Network, the US Geological Survey, SAMIS (S le Analysis Microinformation System), the GFZ Data Services, and the Sparrow software.
Publisher: Copernicus GmbH
Date: 28-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-11348
Abstract: & & Geochemical data are fundamental to understanding many planetary and environmental processes & #8211 yet in the absence of a community-endorsed data culture that adheres to common data standards, the geochemical data landscape is highly fragmented. The GEOROC and PetDB databases are leading, open-access resources for geochemical and isotopic rock and mineral data that have collaborated for nearly 25 years to provide researchers with access to large volumes of curated and harmonized data collections. PetDB is a global synthesis of published chemical, isotopic and mineralogical data for rocks, minerals and melt inclusions with a focus on data for igneous and metamorphic rocks from the ocean floor, ophiolites, xenolith s les from the Earth's mantle and lower crust and tephra, operated by the EarthChem data facility. Its counterpart, GEOROC hosts a collection of published analyses of volcanic and plutonic rocks, minerals and mantle xenoliths, predominantly derived from ocean islands and continental settings. These curated, domain-specific databases are increasingly valuable to data-driven and interdisciplinary research and form the basis of hundreds of new research articles each year across numerous earth data disciplines.& & & & & Over the last two decades, both GEOROC and EarthChem have invested great efforts into operating data infrastructures for findable, accessible, interoperable and reusable data, while working together to develop and maintain the EarthChem Portal (ECP) as a global open data service to the geochemical, petrological, mineralogical and related communities. The ECP provides a single point of access to & million analytical values for & million s les, aggregated from independently operated databases (PetDB, NAVDAT, GEOROC, USGS, MetPetDB, DARWIN). Yet one crucial element of FAIR data is still largely missing: interoperability across different data systems, that allows data in separately curated databases, such as GEOROC and PetDB, to be integrated into comprehensive, global geochemical datasets.& & & & Both EarthChem and GEOROC have recently embarked on major new developments and upgrades to their systems to improve the interoperability of their data systems. The new Digital Geochemical Data Infrastructure (DIGIS) initiative for GEOROC 2.0 aims to develop a connected platform to meet future challenges of digital data-based research and provide advanced services to the community. EarthChem has been developing an API-driven architecture to align with growing demands for machine-readable, Analysis Ready Data (ARD). This has presented an opportunity to make the two data infrastructures more interoperable and complementary. EarthChem and DIGIS have committed to cooperation on system architecture design, data models, data curation, methodologies, best practices and standards for geochemistry. This cooperation will include: (a) joint research projects (b) optimized coordination and alignment of technologies, procedures and community engagement and (c) exchange of personnel, data, technology and information. The EarthChem-DIGIS collaboration integrates with the international OneGeochemistry initiative to create a global geochemical data network that facilitates and promotes discovery and access of geochemical data through coordination and collaboration among international geochemical data providers, in close dialogue with the scientific community and with journal publishers.& &
Publisher: AIP Publishing
Date: 28-01-2019
DOI: 10.1063/1.5085121
Abstract: Processes related to electronically excited states are central in many areas of science however, accurately determining excited-state energies remains a major challenge in theoretical chemistry. Recently, higher energy stationary states of non-linear methods have themselves been proposed as approximations to excited states, although the general understanding of the nature of these solutions remains surprisingly limited. In this letter, we present an entirely novel approach for exploring and obtaining excited stationary states by exploiting the properties of non-Hermitian Hamiltonians. Our key idea centres on performing analytic continuations of conventional quantum chemistry methods. Considering Hartree-Fock theory as an ex le, we analytically continue the electron-electron interaction to expose a hidden connectivity of multiple solutions across the complex plane, revealing a close resemblance between Coulson-Fischer points and non-Hermitian degeneracies. Finally, we demonstrate how a ground-state wave function can be morphed naturally into an excited-state wave function by constructing a well-defined complex adiabatic connection.
Publisher: American Chemical Society (ACS)
Date: 05-06-2019
Abstract: PT-symmetry-invariance with respect to combined space reflection P and time reversal T-provides a weaker condition than (Dirac) Hermiticity for ensuring a real energy spectrum of a general non-Hermitian Hamiltonian. PT-symmetric Hamiltonians therefore form an intermediate class between Hermitian and non-Hermitian Hamiltonians. In this work, we derive the conditions for PT-symmetry in the context of electronic structure theory and, specifically, within the Hartree-Fock (HF) approximation. We show that the HF orbitals are symmetric with respect to the PT operator
Publisher: American Chemical Society (ACS)
Date: 20-03-2019
DOI: 10.26434/CHEMRXIV.7868351.V1
Abstract: P T -symmetry — invariance with respect to combined space reflection P and time reversal T — provides a weaker condition than (Dirac) Hermiticity for ensuring a real energy spectrum of a general non-Hermitian Hamiltonian. PT -symmetric Hamiltonians therefore form an intermediate class between Hermitian and non-Hermitian Hamiltonians. In this work, we derive the conditions for PT-symmetry in the context of electronic structure theory, and specifically, within the Hartree–Fock (HF) approximation. We show that the HF orbitals are symmetric with respect to the P T operator if and only if the effective Fock Hamiltonian is PT -symmetric, and vice versa. By extension, if an optimal self-consistent solution is invariant under PT , then its eigenvalues and corresponding HF energy must be real. Moreover, we demonstrate how one can construct explicitly PT -symmetric Slater determinants by forming PT doublets (i.e. pairing each occupied orbital with its PT -transformed analogue), allowing PT -symmetry to be conserved throughout the self-consistent process. Finally, considering the H2 molecule as an illustrative ex le, we observe PT-symmetry in the HF energy landscape and find that the symmetry-broken unrestricted HF wave functions (i.e. diradical configurations) are P T -symmetric, while the symmetry-broken restricted HF wave functions (i.e. ionic configurations) break PT -symmetry.
Location: China
No related grants have been discovered for Peng Ji.