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  1. Article ; Online: Improved Local-Mode Zero-Point-Energy Conservation Scheme for Quasiclassical Trajectories.

    Shu, Yinan / Truhlar, Donald G

    The journal of physical chemistry. A

    2024  

    Abstract: We present an improvement of the local-pair zero-point-energy (LP-ZPE) scheme of Mukherjee and Barbatti. The new approximation is called the improved LP-ZPE scheme or iLP-ZPE. This scheme can produce trajectories that do not have unphysical leaking of ... ...

    Abstract We present an improvement of the local-pair zero-point-energy (LP-ZPE) scheme of Mukherjee and Barbatti. The new approximation is called the improved LP-ZPE scheme or iLP-ZPE. This scheme can produce trajectories that do not have unphysical leaking of zero-point energy from high-frequency spectator modes into low-frequency modes. We illustrate the method with a successful direct dynamics application to the Ne···HF van der Waals molecule. The method is well suited for direct dynamics calculations because it does not require costly evaluations of local Hessians or instantaneous normal modes along the trajectories.
    Language English
    Publishing date 2024-04-26
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5215
    ISSN (online) 1520-5215
    DOI 10.1021/acs.jpca.3c08309
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Electronic Excitation of

    Ning, Jiaxin / Truhlar, Donald G

    The journal of physical chemistry. A

    2023  Volume 127, Issue 6, Page(s) 1469–1474

    Abstract: ... ...

    Abstract ortho
    Language English
    Publishing date 2023-02-07
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5215
    ISSN (online) 1520-5215
    DOI 10.1021/acs.jpca.2c08674
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Chemical Bonding in Isoelectronic NdO

    Ning, Jiaxin / Truhlar, Donald G

    The journal of physical chemistry. A

    2023  Volume 127, Issue 10, Page(s) 2295–2305

    Abstract: Neodymium dioxide ( ... ...

    Abstract Neodymium dioxide (NdO
    Language English
    Publishing date 2023-03-07
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5215
    ISSN (online) 1520-5215
    DOI 10.1021/acs.jpca.2c08461
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Decoherence and Its Role in Electronically Nonadiabatic Dynamics.

    Shu, Yinan / Truhlar, Donald G

    Journal of chemical theory and computation

    2023  

    Abstract: Decoherence is the tendency of a time-evolved reduced density matrix for a subsystem to assume a form corresponding to a statistical ensemble of states rather than a coherent combination of pure-state wave functions. When a molecular process involves ... ...

    Abstract Decoherence is the tendency of a time-evolved reduced density matrix for a subsystem to assume a form corresponding to a statistical ensemble of states rather than a coherent combination of pure-state wave functions. When a molecular process involves changes in the electronic state and the coordinates of the nuclei, as in ultraviolet or visible light photochemistry or electronically inelastic collisions, the reduced density matrix of the electronic subsystem suffers decoherence, due to its interaction with the nuclear subsystem. We present the background necessary to conceptualize this decoherence; in particular, we discuss the density matrix description of pure states and mixed states, and we discuss pointer states and decoherence time. We then discuss how decoherence is treated in the coherent switching with decay of mixing algorithm and the trajectory surface hopping method for semiclassical calculations of electronically nonadiabatic processes.
    Language English
    Publishing date 2023-01-09
    Publishing country United States
    Document type Journal Article ; Review
    ISSN 1549-9626
    ISSN (online) 1549-9626
    DOI 10.1021/acs.jctc.2c00988
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: An Accurate Density Coherence Functional for Hybrid Multiconfiguration Density Coherence Functional Theory.

    Zhang, Dayou / Truhlar, Donald G

    Journal of chemical theory and computation

    2023  Volume 19, Issue 19, Page(s) 6551–6556

    Abstract: We present hybrid multiconfiguration density coherence functional theory (HMC-DCFT), and we optimize a density coherence functional by parametrization against a diverse data set of 59 bond energies and 60 barrier heights. We compare the results to ... ...

    Abstract We present hybrid multiconfiguration density coherence functional theory (HMC-DCFT), and we optimize a density coherence functional by parametrization against a diverse data set of 59 bond energies and 60 barrier heights. We compare the results to calculations on the same data set by CASSCF, CASPT2, six Kohn-Sham and hybrid Kohn-Sham exchange-correlation functionals, and three on-top functionals for pair-density functional theory (PDFT) and hybrid PDFT. The new functional has better accuracy than all compared methods.
    Language English
    Publishing date 2023-09-14
    Publishing country United States
    Document type Journal Article
    ISSN 1549-9626
    ISSN (online) 1549-9626
    DOI 10.1021/acs.jctc.3c00741
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Parametrically Managed Activation Functions for Improved Global Potential Energy Surfaces for Six Coupled

    Shu, Yinan / Akher, Farideh Badichi / Guo, Hua / Truhlar, Donald G

    The journal of physical chemistry. A

    2024  Volume 128, Issue 7, Page(s) 1207–1217

    Abstract: We report new potential energy surfaces for six ... ...

    Abstract We report new potential energy surfaces for six coupled
    Language English
    Publishing date 2024-02-13
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5215
    ISSN (online) 1520-5215
    DOI 10.1021/acs.jpca.3c06823
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Unimolecular Reactions of

    Sun, Yan / Long, Bo / Truhlar, Donald G

    Research (Washington, D.C.)

    2023  Volume 6, Page(s) 143

    Abstract: The kinetics of Criegee intermediates are important for atmospheric modeling. However, the quantitative kinetics of Criegee intermediates are still very limited, especially for those with hydroxy groups. Here, we calculate rate constants for the ... ...

    Abstract The kinetics of Criegee intermediates are important for atmospheric modeling. However, the quantitative kinetics of Criegee intermediates are still very limited, especially for those with hydroxy groups. Here, we calculate rate constants for the unimolecular reaction of
    Language English
    Publishing date 2023-07-10
    Publishing country United States
    Document type Journal Article
    ISSN 2639-5274
    ISSN (online) 2639-5274
    DOI 10.34133/research.0143
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Analytic Nuclear Gradients for Complete Active Space Linearized Pair-Density Functional Theory.

    Hennefarth, Matthew R / Hermes, Matthew R / Truhlar, Donald G / Gagliardi, Laura

    Journal of chemical theory and computation

    2024  

    Abstract: Accurately modeling photochemical reactions is difficult due to the presence of conical intersections and locally avoided crossings, as well as the inherently multiconfigurational character of excited states. As such, one needs a multistate method that ... ...

    Abstract Accurately modeling photochemical reactions is difficult due to the presence of conical intersections and locally avoided crossings, as well as the inherently multiconfigurational character of excited states. As such, one needs a multistate method that incorporates state interaction in order to accurately model the potential energy surface at all nuclear coordinates. The recently developed linearized pair-density functional theory (L-PDFT) is a multistate extension of multiconfiguration PDFT, and it has been shown to be a cost-effective post-MCSCF method (as compared to more traditional and expensive multireference many-body perturbation methods or multireference configuration interaction methods) that can accurately model potential energy surfaces in regions of strong nuclear-electronic coupling in addition to accurately predicting Franck-Condon vertical excitations. In this paper, we report the derivation of analytic gradients for L-PDFT and their implementation in the PySCF-forge software, and we illustrate the utility of these gradients for predicting ground- and excited-state equilibrium geometries and adiabatic excitation energies for formaldehyde,
    Language English
    Publishing date 2024-04-19
    Publishing country United States
    Document type Journal Article
    ISSN 1549-9626
    ISSN (online) 1549-9626
    DOI 10.1021/acs.jctc.4c00095
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  9. Article ; Online: Simple Approximation for the Ideal Reference State of Gases Adsorbed on Solid-State Surfaces.

    Ye, Jingyun / Truhlar, Donald G

    Journal of the American Chemical Society

    2022  Volume 144, Issue 28, Page(s) 12850–12860

    Abstract: Reference states are useful as models for facilitating calculations of equilibrium constants, and they may also serve as standard states that are convenient for organizing and tabulating thermodynamic data; however, standard state conventions and ... ...

    Abstract Reference states are useful as models for facilitating calculations of equilibrium constants, and they may also serve as standard states that are convenient for organizing and tabulating thermodynamic data; however, standard state conventions and appropriate reference states for adsorbed species have received less attention than those for pure substances and solutes. Here, we compare seven choices of reference states for calculations of equilibrium constants and transition state theory rate constants for flat surfaces, in particular (1) an ideal 2D harmonic oscillator, (2) an ideal rigid-molecule harmonic oscillator, (3) an ideal 2D harmonic oscillator with separable surface modes, (4) a 2D ideal gas, (5) an ideal 2D hindered translator, (6) an ideal 2D hindered translator with lowest-order barriers, and (7) a simple ideal 2D hindered translator proposed in this work. The advantage of models 5-7 is that they can treat both mobile and localized adsorbates in a consistent way, whereas models 1-3 are only appropriate for localized adsorbates, and model 4 is only appropriate for a freely translating adsorbate. Furthermore, models 6 and 7 reduce the computational cost without the user having to calculate barrier heights for diffusion. An advantage of the simple ideal 2D hindered translator is that it has a physical high-temperature limit. We also propose a reference state for nonflat surfaces. The user is encouraged to choose a reference state based on the appropriateness of the model and the practicality of the calculations.
    MeSH term(s) Diffusion ; Entropy ; Gases ; Solutions ; Thermodynamics
    Chemical Substances Gases ; Solutions
    Language English
    Publishing date 2022-07-05
    Publishing country United States
    Document type Journal Article ; Research Support, U.S. Gov't, Non-P.H.S.
    ZDB-ID 3155-0
    ISSN 1520-5126 ; 0002-7863
    ISSN (online) 1520-5126
    ISSN 0002-7863
    DOI 10.1021/jacs.2c04333
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  10. Article ; Online: Semiclassical Multistate Dynamics for Six Coupled

    Akher, Farideh Badichi / Shu, Yinan / Varga, Zoltan / Truhlar, Donald G

    Journal of chemical theory and computation

    2023  Volume 19, Issue 14, Page(s) 4389–4401

    Abstract: Dynamics simulations of high-energy ... ...

    Abstract Dynamics simulations of high-energy O
    Language English
    Publishing date 2023-07-13
    Publishing country United States
    Document type Journal Article
    ISSN 1549-9626
    ISSN (online) 1549-9626
    DOI 10.1021/acs.jctc.3c00517
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