A previous study of diatomic molecules revealed that variational second-order density matrix theory has serious problems in the dissociation limit when the N-representability is imposed at the level of the usual two-index (P,Q,G) or even three-index (T(1),T(2)) conditions [H. Van Aggelen et al., Phys. Chem. Chem. Phys. 11, 5558 (2009)]. Heteronuclear molecules tend to dissociate into fractionally charged atoms. In this paper we introduce a general class of N-representability conditions, called subsystem constraints, and show that they cure the dissociation problem at little additional computational cost. As a numerical example the singlet potential energy surface of Be B(+) is studied. The extension to polyatomic molecules, where more subsystem choices can be identified, is also discussed.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1063/1.3354911 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
The tight balance state and mechanism of disaster-resilient resources in karst small towns: a Chinese karst landform case study.
Sci Rep
January 2025
College of Architecture and Urban Planning, Guizhou University, Guiyang, 550025, China.
Karst small towns globally face challenges due to limited disaster-resilient resources, making it difficult to handle increasingly severe disaster environments. Improving the efficiency of disaster-resilient resource utilization and maintaining a tight balance state of disaster-resilient resources (TBS) are crucial for enhancing disaster adaptability and resilience. This study used urban and disaster data from a representative karst region in China (2017-2021) to conduct a quantitative analysis of TBS in karst small towns, exploring the mechanisms and interactions within this state and identifying obstacle factors.
View Article and Find Full Text PDFIntegrating crop and dairy production systems: Exploring different strategies to achieve environmental targets.
Sci Total Environ
January 2025
Wageningen University & Research, Animal Production Systems Group, 6706 WD Wageningen, the Netherlands; Christian Albrechts University, Grass and Forage Science/Organic Agriculture, D-24118 Kiel, Germany.
The integration between crop and livestock production systems (ICLS) at regional level is seen as a pathway for more sustainable food production. The objective was to assess the effects on farm structure, economic performance and environmental impact of an ICLS with varying constraints on agricultural emissions, changes in land use and a lower external input use as means to achieve environmental targets. A linear optimization model was used for economic optimization of ICLS under different scenarios for the case of crop and dairy production systems on sandy soils in the Netherlands.
View Article and Find Full Text PDFResearch on state machine control optimization of double-stack fuel cell/super capacitor hybrid system.
PLoS One
November 2024
Dalian Naval Academy, Zhongshan District, Dalian City, Liaoning Province, China.
To ensure the continuous high-efficiency operation of fuel cell systems, it is essential to perform real-time estimation of the maximum efficiency point and maximum power point for multi-stack fuel cell systems. The region between these two power points is commonly referred to as the "high-efficiency operating region." Initially, a transformation of the general expression for hydrogen consumption in multi-stack fuel cell systems is conducted to obtain an algebraic expression for the efficiency curve of multi-stack fuel cells.
View Article and Find Full Text PDFBarrier-critic-disturbance approximate optimal control of nonzero-sum differential games for modular robot manipulators.
Neural Netw
January 2025
Department of Control Science and Engineering, Changchun University of Technology, Changchun, 130012, Jilin, China.
In this paper, for addressing the safe control problem of modular robot manipulators (MRMs) system with uncertain disturbances, an approximate optimal control scheme of nonzero-sum (NZS) differential games is proposed based on the control barrier function (CBF). The dynamic model of the manipulator system integrates joint subsystems through the utilization of joint torque feedback (JTF) technique, incorporating interconnected dynamic coupling (IDC) effects. By integrating the cost functions relevant to each player with the CBF, the evolution of system states is ensured to remain within the safe region.
View Article and Find Full Text PDFDetermining the -Representability of a Reduced Density Matrix via Unitary Evolution and Stochastic Sampling.
J Chem Theory Comput
November 2024
Department of Chemistry, Rice University, Houston, Texas 77005-1892, United States.
Article Synopsis
- The -representability problem aims to determine if a given -body matrix can be derived from a corresponding -body density matrix through contraction, which is crucial for finding a system's exact ground state.
- Understanding the complete conditions for -representability is complicated due to the exponential growth of constraints with the size of the system, making it impractical for larger applications.
- The study introduces a hybrid quantum-stochastic algorithm to replace traditional -representability checks, utilizing adaptive unitary evolution and a simulated annealing process to efficiently assess and improve the quality of -body matrices from various quantum models.
Want AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!