LIVIVO - The Search Portal for Life Sciences

zur deutschen Oberfläche wechseln
Advanced search

Search results

Result 1 - 10 of total 63

Search options

  1. Article ; Online: Electronic Coherences Excited by an Ultra Short Pulse Are Robust with Respect to Averaging over Randomly Oriented Molecules as Shown by Singular Value Decomposition.

    Cardosa-Gutierrez, Manuel / Levine, Raphael D / Remacle, Francoise

    The journal of physical chemistry. A

    2024  Volume 128, Issue 15, Page(s) 2937–2947

    Abstract: We report a methodology for averaging quantum photoexcitation vibronic dynamics over the initial orientations of the molecules with respect to an ultrashort light pulse. We use singular value decomposition of the ensemble density matrix of the excited ... ...

    Abstract We report a methodology for averaging quantum photoexcitation vibronic dynamics over the initial orientations of the molecules with respect to an ultrashort light pulse. We use singular value decomposition of the ensemble density matrix of the excited molecules, which allows the identification of the few dominant principal molecular orientations with respect to the polarization direction of the electric field. The principal orientations provide insights into the specific stereodynamics of the corresponding principal molecular vibronic states. The massive compaction of the vibronic density matrix of the ensemble of randomly oriented pumped molecules enables a most efficient fully quantum mechanical time propagation scheme. Two examples are discussed for the quantum dynamics of the LiH molecule in the manifolds of its electronically excited Σ and Π states. Our results show that electronic and vibrational coherences between excited states of the same symmetry are resilient to averaging over an ensemble of molecular orientations and can be selectively excited at the ensemble level by tuning the pulse parameters.
    Language English
    Publishing date 2024-04-03
    Publishing country United States
    Document type Journal Article
    ISSN 1520-5215
    ISSN (online) 1520-5215
    DOI 10.1021/acs.jpca.3c07856
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  2. Article ; Online: Nonadiabatic quantum dynamics explores non-monotonic photodissociation branching of N

    Gelfand, Natalia / Komarova, Ksenia / Remacle, Francoise / Levine, R D

    Physical chemistry chemical physics : PCCP

    2024  Volume 26, Issue 4, Page(s) 3274–3284

    Abstract: Vacuum ultraviolet (VUV) photodissociation of ... ...

    Abstract Vacuum ultraviolet (VUV) photodissociation of N
    Language English
    Publishing date 2024-01-24
    Publishing country England
    Document type Journal Article
    ZDB-ID 1476244-4
    ISSN 1463-9084 ; 1463-9076
    ISSN (online) 1463-9084
    ISSN 1463-9076
    DOI 10.1039/d3cp04854c
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  3. Article ; Online: Recombination of N Atoms in a Manifold of Electronic States Simulated by Time-Reversed Nonadiabatic Photodissociation Dynamics of N

    Gelfand, Natalia / Remacle, Francoise / Levine, Raphael D

    The journal of physical chemistry letters

    2023  Volume 14, Issue 19, Page(s) 4625–4630

    Abstract: Following a single photon VUV absorption, the ... ...

    Abstract Following a single photon VUV absorption, the N
    Language English
    Publishing date 2023-05-11
    Publishing country United States
    Document type Journal Article
    ISSN 1948-7185
    ISSN (online) 1948-7185
    DOI 10.1021/acs.jpclett.3c00666
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  4. Article ; Online: Nonadiabatic dynamics in a forest of coupled states: Electronic state branching in the VUV photodissociation of N2.

    Gelfand, Natalia / Komarova, Ksenia / Remacle, Françoise / Levine, Raphael D

    The Journal of chemical physics

    2023  Volume 158, Issue 16

    Abstract: Multi-state electronic dynamics at higher excitation energies is needed for the understanding of a variety of energy rich situations, including chemistry under extreme conditions, vacuum ultraviolet (VUV) induced astrochemistry, and attochemistry. It ... ...

    Abstract Multi-state electronic dynamics at higher excitation energies is needed for the understanding of a variety of energy rich situations, including chemistry under extreme conditions, vacuum ultraviolet (VUV) induced astrochemistry, and attochemistry. It calls for an understanding of three stages, energy acquisition, dynamical propagation, and disposal. It is typically not possible to identify a basis of uncoupled quantum states that is sufficient for the three stages. The handicap is the large number of coupled quantum states that is needed to describe the system. Progress in quantum chemistry provides the necessary background to the energetics and the coupling. Progress in quantum dynamics takes this as input for the propagation in time. Right now, it seems that we have come of age with potential detailed applications. We here report a demonstration to a coupled electron-nuclear quantum dynamics through a maze of 47 electronic states and with attention to the order in perturbation theory that is indicated using propensity rules for couplings. Close agreement with experimental results for the VUV photodissociation of 14N2 and its isotopomer 14N15N is achieved. We pay special attention to the coupling between two dissociative continua and an optically accessible bound domain. The computations reproduce and interpret the non-monotonic branching between the two exit channels producing N(2D) and N(2P) atoms as a function of excitation energy and its variation with the mass.
    Language English
    Publishing date 2023-04-27
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3113-6
    ISSN 1089-7690 ; 0021-9606
    ISSN (online) 1089-7690
    ISSN 0021-9606
    DOI 10.1063/5.0148798
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  5. Article ; Online: Compacting the density matrix in quantum dynamics: Singular value decomposition of the surprisal and the dominant constraints for anharmonic systems.

    Komarova, K / Remacle, Francoise / Levine, R D

    The Journal of chemical physics

    2021  Volume 155, Issue 20, Page(s) 204110

    Abstract: We introduce a practical method for compacting the time evolution of the quantum state of a closed physical system. The density matrix is specified as a function of a few time-independent observables where their coefficients are time-dependent. The key ... ...

    Abstract We introduce a practical method for compacting the time evolution of the quantum state of a closed physical system. The density matrix is specified as a function of a few time-independent observables where their coefficients are time-dependent. The key mathematical step is the vectorization of the surprisal, the logarithm of the density matrix, at each time point of interest. The time span used depends on the required spectral resolution. The entire course of the system evolution is represented as a matrix where each column is the vectorized surprisal at the given time point. Using the singular value decomposition (SVD) of this matrix, we generate realistic approximations for the time-independent observables and their respective time-dependent coefficients. This allows for a simplification of the algebraic procedure for determining the dominant constraints (the time-independent observables) in the sense of the maximal entropy approach. A non-stationary coherent initial state of a Morse oscillator is used to introduce the approach. We derive the analytical exact expression for the surprisal as a function of time, and this offers a benchmark for comparison with the accurate but approximate SVD results. We discuss two examples of a Morse potential of different anharmonicities, H
    Language English
    Publishing date 2021-12-01
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3113-6
    ISSN 1089-7690 ; 0021-9606
    ISSN (online) 1089-7690
    ISSN 0021-9606
    DOI 10.1063/5.0072351
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  6. Article ; Online: Identification of an ultrafast internal conversion pathway of pyrazine by time-resolved vacuum ultraviolet photoelectron spectrum simulations.

    Kanno, Manabu / Mignolet, Benoît / Remacle, Françoise / Kono, Hirohiko

    The Journal of chemical physics

    2021  Volume 154, Issue 22, Page(s) 224304

    Abstract: The internal conversion from the optically bright ... ...

    Abstract The internal conversion from the optically bright S
    Language English
    Publishing date 2021-06-17
    Publishing country United States
    Document type Journal Article
    ZDB-ID 3113-6
    ISSN 1089-7690 ; 0021-9606
    ISSN (online) 1089-7690
    ISSN 0021-9606
    DOI 10.1063/5.0048900
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  7. Article: Bond breaking of furan-maleimide adducts

    Cardosa-Gutierrez, Manuel / De Bo, Guillaume / Duwez, Anne-Sophie / Remacle, Francoise

    Chemical science

    2023  Volume 14, Issue 5, Page(s) 1263–1271

    Abstract: Substituted furan-maleimide Diels-Alder adducts are bound by dynamic covalent bonds that make them particularly attractive mechanophores. Thermally activated [4 + 2] retro-Diels-Alder (DA) reactions predominantly ... ...

    Abstract Substituted furan-maleimide Diels-Alder adducts are bound by dynamic covalent bonds that make them particularly attractive mechanophores. Thermally activated [4 + 2] retro-Diels-Alder (DA) reactions predominantly proceed
    Language English
    Publishing date 2023-01-04
    Publishing country England
    Document type Journal Article
    ZDB-ID 2559110-1
    ISSN 2041-6539 ; 2041-6520
    ISSN (online) 2041-6539
    ISSN 2041-6520
    DOI 10.1039/d2sc05051j
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  8. Article: Correction: Bond breaking of furan-maleimide adducts

    Cardosa-Gutierrez, Manuel / De Bo, Guillaume / Duwez, Anne-Sophie / Remacle, Francoise

    Chemical science

    2023  Volume 14, Issue 9, Page(s) 2467

    Abstract: This corrects the article DOI: 10.1039/D2SC05051J.]. ...

    Abstract [This corrects the article DOI: 10.1039/D2SC05051J.].
    Language English
    Publishing date 2023-02-15
    Publishing country England
    Document type Published Erratum
    ZDB-ID 2559110-1
    ISSN 2041-6539 ; 2041-6520
    ISSN (online) 2041-6539
    ISSN 2041-6520
    DOI 10.1039/d3sc90024j
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

  9. Book ; Online: A quantum annealing-sequential quadratic programming assisted finite element simulation for non-linear and history-dependent mechanical problems

    Nguyen, Van-Dung / Wu, Ling / Remacle, Françoise / Noels, Ludovic

    2023  

    Abstract: We propose a framework to solve non-linear and history-dependent mechanical problems based on a hybrid classical computer -- quantum annealer approach. Quantum Computers are anticipated to solve particular operations exponentially faster. The available ... ...

    Abstract We propose a framework to solve non-linear and history-dependent mechanical problems based on a hybrid classical computer -- quantum annealer approach. Quantum Computers are anticipated to solve particular operations exponentially faster. The available possible operations are however not as versatile as with a classical computer. However, quantum annealers (QAs) are well suited to evaluate the minimum state of a Hamiltonian quadratic potential. Therefore, we reformulate the elasto-plastic finite element problem as a double-minimisation process framed at the structural scale using the variational updates formulation. In order to comply with the expected quadratic nature of the Hamiltonian, the resulting non-linear minimisation problems are iteratively solved with the suggested Quantum Annealing-assisted Sequential Quadratic Programming (QA-SQP): a sequence of minimising quadratic problems is performed by approximating the objective function by a quadratic Taylor's series. Each quadratic minimisation problem of continuous variables is then transformed into a binary quadratic problem. This binary quadratic minimisation problem can be solved on quantum annealing hardware such as the D-Wave system. The applicability of the proposed framework is demonstrated with one- and two-dimensional elasto-plastic numerical benchmarks. The current work provides a pathway of performing general non-linear finite element simulations assisted by quantum computing.

    Comment: This is an updated version following reviewing process. The code and raw/processed data required to reproduce these findings is available on http://dx.doi.org/10.5281/zenodo.10451584 under the Creative Commons Attribution 4.0 International (CC BY 4.0) licence
    Keywords Computer Science - Computational Engineering ; Finance ; and Science
    Subject code 531
    Publishing date 2023-10-10
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

    More links

    Kategorien

  10. Article ; Online: Thermodynamic energetics underlying genomic instability and whole-genome doubling in cancer.

    Remacle, Francoise / Graeber, Thomas G / Levine, R D

    Proceedings of the National Academy of Sciences of the United States of America

    2020  Volume 117, Issue 31, Page(s) 18880–18890

    Abstract: Genomic instability contributes to tumorigenesis through the amplification and deletion of cancer driver genes. DNA copy number (CN) profiling of ensembles of tumors allows a thermodynamic analysis of the profile for each tumor. The free energy of the ... ...

    Abstract Genomic instability contributes to tumorigenesis through the amplification and deletion of cancer driver genes. DNA copy number (CN) profiling of ensembles of tumors allows a thermodynamic analysis of the profile for each tumor. The free energy of the distribution of CNs is found to be a monotonically increasing function of the average chromosomal ploidy. The dependence is universal across several cancer types. Surprisal analysis distinguishes two main known subgroups: tumors with cells that have or have not undergone whole-genome duplication (WGD). The analysis uncovers that CN states having a narrower distribution are energetically more favorable toward the WGD transition. Surprisal analysis also determines the deviations from a fully stable-state distribution. These deviations reflect constraints imposed by tumor fitness selection pressures. The results point to CN changes that are more common in high-ploidy tumors and thus support altered selection pressures upon WGD.
    MeSH term(s) DNA Copy Number Variations/genetics ; Gene Dosage/genetics ; Genome/genetics ; Genomic Instability/genetics ; Humans ; Neoplasms/genetics ; Ploidies ; Thermodynamics
    Language English
    Publishing date 2020-07-21
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Research Support, Non-U.S. Gov't
    ZDB-ID 209104-5
    ISSN 1091-6490 ; 0027-8424
    ISSN (online) 1091-6490
    ISSN 0027-8424
    DOI 10.1073/pnas.1920870117
    Database MEDical Literature Analysis and Retrieval System OnLINE

    More links

    Kategorien

To top