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Xu Q, Liu Y, Wang M, Cerezo J, Improta R, Santoro F. The Resonance Raman Spectrum of Cytosine in Water: Analysis of the Effect of Specific Solute-Solvent Interactions and Non-Adiabatic Couplings. Molecules 2023; 28:molecules28052286. [PMID: 36903532 PMCID: PMC10005559 DOI: 10.3390/molecules28052286] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 02/21/2023] [Accepted: 02/22/2023] [Indexed: 03/06/2023] Open
Abstract
In this contribution, we report a computational study of the vibrational Resonance Raman (vRR) spectra of cytosine in water, on the grounds of potential energy surfaces (PES) computed by time-dependent density functional theory (TD-DFT) and CAM-B3LYP and PBE0 functionals. Cytosine is interesting because it is characterized by several close-lying and coupled electronic states, challenging the approach commonly used to compute the vRR for systems where the excitation frequency is in quasi-resonance with a single state. We adopt two recently developed time-dependent approaches, based either on quantum dynamical numerical propagations of vibronic wavepackets on coupled PES or on analytical correlation functions for cases in which inter-state couplings were neglected. In this way, we compute the vRR spectra, considering the quasi-resonance with the eight lowest-energy excited states, disentangling the role of their inter-state couplings from the mere interference of their different contributions to the transition polarizability. We show that these effects are only moderate in the excitation energy range explored by experiments, where the spectral patterns can be rationalized from the simple analysis of displacements of the equilibrium positions along the different states. Conversely, at higher energies, interference and inter-state couplings play a major role, and the adoption of a fully non-adiabatic approach is strongly recommended. We also investigate the effect of specific solute-solvent interactions on the vRR spectra, by considering a cluster of cytosine, hydrogen-bonded by six water molecules, and embedded in a polarizable continuum. We show that their inclusion remarkably improves the agreement with the experiments, mainly altering the composition of the normal modes, in terms of internal valence coordinates. We also document cases, mostly for low-frequency modes, in which a cluster model is not sufficient, and more elaborate mixed quantum classical approaches, in explicit solvent models, need to be applied.
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Affiliation(s)
- Qiushuang Xu
- School of Physics Engineering, Qufu Normal University, Qufu 273165, China
- School of Physics and Optoelectronics Engineering, Ludong University, Yantai 264025, China
- Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa, Area della Ricerca, Via G. Moruzzi 1, I-56124 Pisa, Italy
| | - Yanli Liu
- School of Physics and Optoelectronics Engineering, Ludong University, Yantai 264025, China
| | - Meishan Wang
- School of Physics Engineering, Qufu Normal University, Qufu 273165, China
- School of Physics and Optoelectronics Engineering, Ludong University, Yantai 264025, China
| | - Javier Cerezo
- Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa, Area della Ricerca, Via G. Moruzzi 1, I-56124 Pisa, Italy
- Departamento de Química and Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Roberto Improta
- Consiglio Nazionale delle Ricerche, Istituto di Biostrutture e Bioimmagini (IBB-CNR), Via De Amicis 95, I-80145 Napoli, Italy
- Correspondence: (R.I.); (F.S.)
| | - Fabrizio Santoro
- Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti Organo Metallici (ICCOM-CNR), SS di Pisa, Area della Ricerca, Via G. Moruzzi 1, I-56124 Pisa, Italy
- Correspondence: (R.I.); (F.S.)
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Lu TF, Wang YS, Tomko JA, Hopkins PE, Zhang HX, Prezhdo OV. Control of Charge Carrier Dynamics in Plasmonic Au Films by TiO x Substrate Stoichiometry. J Phys Chem Lett 2020; 11:1419-1427. [PMID: 32011143 DOI: 10.1021/acs.jpclett.9b03884] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Plasmonic excitations in noble metals have many fascinating properties and give rise to a broad range of applications. We demonstrate, using nonadiabatic molecular dynamics combined with time-domain density functional theory, that the chemical composition and stoichiometry of substrates can have a strong influence on charge dynamics. By changing oxygen content in TiO2, including stoichiometric, oxygen rich, and oxygen poor phases, and Ti metal, one can alter lifetimes of charge carriers in Au by a factor of 5 and control the ratio of electron-to-hole relaxation rates by a factor of 10. Remarkably, a thin TiOx substrate greatly alters charge carrier properties in much thicker Au films. Such large variations stem from the fact that the Ti and O atoms are much lighter than Au, and their vibrations are much faster at dissipating the energy. The control over a particular charge carrier and an energy range depends on the Au and TiOx level alignment, and the interfacial interaction strength. These factors are easily influenced by the TiOx stoichiometry. In particular, oxygen rich and poor TiO2 can be used to control holes and electrons, respectively, while metallic Ti affects both charge carriers. The detailed atomistic analysis of the interfacial and electron-vibrational interactions generates the fundamental understanding of the properties of plasmonic materials needed to design photovoltaic, photocatalytic, optoelectronic, sensing, nanomedical, and other devices.
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Affiliation(s)
- Teng-Fei Lu
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry , Jilin University , Changchun 130023 , People's Republic of China
- Department of Chemistry , University of Southern California , Los Angeles , California 90089 , United States
| | - Yi-Siang Wang
- Department of Chemistry , University of Southern California , Los Angeles , California 90089 , United States
| | - John A Tomko
- Department of Materials Science and Engineering , University of Virginia , Charlottesville , Virginia 22904 , United States
| | - Patrick E Hopkins
- Department of Materials Science and Engineering , University of Virginia , Charlottesville , Virginia 22904 , United States
- Department of Mechanical and Aerospace Engineering , University of Virginia , Charlottesville , Virginia 22904 , United States
- Department of Physics , University of Virginia , Charlottesville , Virginia 22904 , United States
| | - Hong-Xing Zhang
- Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry , Jilin University , Changchun 130023 , People's Republic of China
| | - Oleg V Prezhdo
- Department of Chemistry , University of Southern California , Los Angeles , California 90089 , United States
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Brehm M, Thomas M. Computing Bulk Phase Resonance Raman Spectra from ab Initio Molecular Dynamics and Real-Time TDDFT. J Chem Theory Comput 2019; 15:3901-3905. [PMID: 31246025 DOI: 10.1021/acs.jctc.9b00512] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We present our novel approach for computing resonance Raman (RR) spectra of periodic bulk phase systems from ab initio molecular dynamics, including solvent influence and some anharmonic effects. Based on real-time time-dependent density functional theory, we obtain the RR spectra for all laser wavelengths in one pass. We compute the RR spectrum of uracil in aqueous solution, which is in good agreement with experiment. This is the first simulation of a bulk phase RR spectrum.
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Affiliation(s)
- Martin Brehm
- Institut für Chemie - Theoretische Chemie , Martin-Luther-Universität Halle-Wittenberg , Von-Danckelmann-Platz 4 , 06120 Halle (Saale) , Germany
| | - Martin Thomas
- Institut für Chemie - Theoretische Chemie , Martin-Luther-Universität Halle-Wittenberg , Von-Danckelmann-Platz 4 , 06120 Halle (Saale) , Germany
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Zhang B, Chang R, Wang K, Lü JT, Wang S. Optical Phonon Behaviors of Photocharged Nanocrystals: Effects of Free Charge Carriers. J Phys Chem Lett 2018; 9:5055-5062. [PMID: 30111109 DOI: 10.1021/acs.jpclett.8b01831] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
For semiconductor nanocrystals (NCs), the precise knowledge of phonons in the presence of free carriers is important for understanding their electronic and photonic properties in device applications. With Raman spectroscopy, this study investigates the effects of free charge carriers on optical phonon behaviors of NCs. The adoption of the photocharging method allows us to introduce free charge carriers into NCs without inducing other side effects. In the photocharged ZnO NCs, lower longitudinal optical (LO) phonon frequencies and weaker LO overtones relative to the fundamentals were found, which was explained by the screening and band-filling effects caused by the induced free carriers. The free carrier effects on optical phonon behaviors of NCs, usually neglected in previous studies, should be taken into consideration when discussing the electronic and photonic properties of NC-based devices.
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