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Ranka K, Isborn CM. Size-dependent errors in real-time electron density propagation. J Chem Phys 2023; 158:2887545. [PMID: 37125706 DOI: 10.1063/5.0142515] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 04/14/2023] [Indexed: 05/02/2023] Open
Abstract
Real-time (RT) electron density propagation with time-dependent density functional theory (TDDFT) or Hartree-Fock (TDHF) is one of the most popular methods to model the charge transfer in molecules and materials. However, both RT-TDHF and RT-TDDFT within the adiabatic approximation are known to produce inaccurate evolution of the electron density away from the ground state in model systems, leading to large errors in charge transfer and erroneous shifting of peaks in absorption spectra. Given the poor performance of these methods with small model systems and the widespread use of the methods with larger molecular and material systems, here we bridge the gap in our understanding of these methods and examine the size-dependence of errors in RT density propagation. We analyze the performance of RT density propagation for systems of increasing size during the application of a continuous resonant field to induce Rabi-like oscillations, during charge-transfer dynamics, and for peak shifting in simulated absorption spectra. We find that the errors in the electron dynamics are indeed size dependent for these phenomena, with the largest system producing the results most aligned with those expected from linear response theory. The results suggest that although the RT-TDHF and RT-TDDFT methods may produce severe errors for model systems, the errors in charge transfer and resonantly driven electron dynamics may be much less significant for more realistic, large-scale molecules and materials.
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Affiliation(s)
- Karnamohit Ranka
- Chemistry and Biochemistry, University of California Merced, Merced, California 95343, USA
| | - Christine M Isborn
- Chemistry and Biochemistry, University of California Merced, Merced, California 95343, USA
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Gupta P, Bhat HS, Ranka K, Isborn CM. Statistical Learning for Predicting Density‐Matrix Based Electron Dynamics. Stat (Int Stat Inst) 2021. [DOI: 10.1002/sta4.439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Prachi Gupta
- Chemistry and Biochemistry University of California Merced CA USA
- Applied Mathematics University of California Merced CA USA
| | - Harish S. Bhat
- Applied Mathematics University of California Merced CA USA
| | - Karnamohit Ranka
- Chemistry and Biochemistry University of California Merced CA USA
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Ranka K, Zhao N, Yu L, Stanton JF, Polfer NC. Radical Rearrangement Chemistry in Ultraviolet Photodissociation of Iodotyrosine Systems: Insights from Metastable Dissociation, Infrared Ion Spectroscopy, and Reaction Pathway Calculations. J Am Soc Mass Spectrom 2018; 29:1791-1801. [PMID: 29845561 DOI: 10.1007/s13361-018-1959-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 03/21/2018] [Accepted: 04/01/2018] [Indexed: 06/08/2023]
Abstract
We report on the ultraviolet photodissociation (UVPD) chemistry of protonated tyrosine, iodotyrosine, and diiodotyrosine. Distonic loss of the iodine creates a high-energy radical at the aromatic ring that engages in hydrogen/proton rearrangement chemistry. Based on UVPD kinetics measurements, the appearance of this radical is coincident with the UV irradiation pulse (8 ns). Conversely, sequential UVPD product ions exhibit metastable decay on ca. 100 ns timescales. Infrared ion spectroscopy is capable of confirming putative structures of the rearrangement products as proton transfers from the imine and β-carbon hydrogens. Potential energy surfaces for the various reaction pathways indicate that the rearrangement chemistry is highly complex, compatible with a cascade of rearrangements, and that there is no preferred rearrangement pathway even in small molecular systems like these. Graphical Abstract.
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Affiliation(s)
- Karnamohit Ranka
- Quantum Theory Project, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL, 32611-7200, USA
- Quantum Theory Project, Department of Physics, University of Florida, P.O. Box 118435, Gainesville, FL, 32611-8435, USA
| | - Ning Zhao
- Department of Chemistry and Center for Chemical Physics, University of Florida, P.O. Box 117200, Gainesville, FL, 32611-7200, USA
| | - Long Yu
- Department of Chemistry and Center for Chemical Physics, University of Florida, P.O. Box 117200, Gainesville, FL, 32611-7200, USA
| | - John F Stanton
- Quantum Theory Project, Department of Chemistry, University of Florida, P.O. Box 117200, Gainesville, FL, 32611-7200, USA
- Quantum Theory Project, Department of Physics, University of Florida, P.O. Box 118435, Gainesville, FL, 32611-8435, USA
| | - Nicolas C Polfer
- Department of Chemistry and Center for Chemical Physics, University of Florida, P.O. Box 117200, Gainesville, FL, 32611-7200, USA.
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Ranka K, Perera A, Bartlett RJ. Elementary reaction profile and chemical kinetics study of [C(1D)/(3P) + SiH4] with the CCSD(T) method. Chem Phys Lett 2017. [DOI: 10.1016/j.cplett.2017.05.024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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