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Tao Y, Zou W, Cremer D, Kraka E. Correlating the vibrational spectra of structurally related molecules: A spectroscopic measure of similarity. J Comput Chem 2017; 39:293-306. [PMID: 29143968 DOI: 10.1002/jcc.25109] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 10/16/2017] [Accepted: 10/22/2017] [Indexed: 01/24/2023]
Abstract
Using catastrophe theory and the concept of a mutation path, an algorithm is developed that leads to the direct correlation of the normal vibrational modes of two structurally related molecules. The mutation path is defined by weighted incremental changes in mass and geometry of the molecules in question, which are successively applied to mutate a molecule into a structurally related molecule and thus continuously converting their normal vibrational spectra from one into the other. Correlation diagrams are generated that accurately relate the normal vibrational modes to each other by utilizing mode-mode overlap criteria and resolving allowed and avoided crossings of vibrational eigenstates. The limitations of normal mode correlation, however, foster the correlation of local vibrational modes, which offer a novel vibrational measure of similarity. It will be shown how this will open new avenues for chemical studies. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Yunwen Tao
- Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, Texas, 75275-0314
| | - Wenli Zou
- Institute of Modern Physics, Northwest University, Xi'an, Shaanxi, 710127, People's Republic of China
| | - Dieter Cremer
- Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, Texas, 75275-0314
| | - Elfi Kraka
- Department of Chemistry, Southern Methodist University, 3215 Daniel Avenue, Dallas, Texas, 75275-0314
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Manley ME, Abernathy DL, Sahul R, Parshall DE, Lynn JW, Christianson AD, Stonaha PJ, Specht ED, Budai JD. Giant electromechanical coupling of relaxor ferroelectrics controlled by polar nanoregion vibrations. Sci Adv 2016; 2:e1501814. [PMID: 27652338 PMCID: PMC5026422 DOI: 10.1126/sciadv.1501814] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 08/10/2016] [Indexed: 06/06/2023]
Abstract
Relaxor-based ferroelectrics are prized for their giant electromechanical coupling and have revolutionized sensor and ultrasound applications. A long-standing challenge for piezoelectric materials has been to understand how these ultrahigh electromechanical responses occur when the polar atomic displacements underlying the response are partially broken into polar nanoregions (PNRs) in relaxor-based ferroelectrics. Given the complex inhomogeneous nanostructure of these materials, it has generally been assumed that this enhanced response must involve complicated interactions. By using neutron scattering measurements of lattice dynamics and local structure, we show that the vibrational modes of the PNRs enable giant coupling by softening the underlying macrodomain polarization rotations in relaxor-based ferroelectric PMN-xPT {(1 - x)[Pb(Mg1/3Nb2/3)O3] - xPbTiO3} (x = 30%). The mechanism involves the collective motion of the PNRs with transverse acoustic phonons and results in two hybrid modes, one softer and one stiffer than the bare acoustic phonon. The softer mode is the origin of macroscopic shear softening. Furthermore, a PNR mode and a component of the local structure align in an electric field; this further enhances shear softening, revealing a way to tune the ultrahigh piezoelectric response by engineering elastic shear softening.
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Affiliation(s)
- Michael E. Manley
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Douglas L. Abernathy
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Raffi Sahul
- TRS Technologies, State College, PA 16801, USA
| | - Daniel E. Parshall
- NIST Center for Neutron Research, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA
| | - Jeffrey W. Lynn
- NIST Center for Neutron Research, National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899, USA
| | - Andrew D. Christianson
- Quantum Condensed Matter Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Paul J. Stonaha
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Eliot D. Specht
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - John D. Budai
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
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Buchanan EG, Gord JR, Zwier TS. Solvent Effects on Vibronic Coupling in a Flexible Bichromophore: Electronic Localization and Energy Transfer induced by a Single Water Molecule. J Phys Chem Lett 2013; 4:1644-1648. [PMID: 26282972 DOI: 10.1021/jz400641p] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Size and conformation-specific ultraviolet and infrared spectra are used to probe the effects of binding a single water molecule on the close-lying excited states present in a model flexible bichromophore, 1,2-diphenoxyethane (DPOE). The water molecule binds to DPOE asymmetrically, thereby localizing the two electronically excited states on one or the other ring, producing a S1/S2 splitting of 190 cm(-1). Electronic localization is reflected clearly in the OH stretch transitions in the excited states. Since the S2 origin is imbedded in vibronic levels of the S1 manifold, its OH stretch spectrum reflects the vibronic coupling between these levels, producing four OH stretch transitions that are a sum of contributions from S2-localized and S1-localized excited states. The single solvent water molecule thus plays multiple roles, localizing the electronic excitation in the bichromophore, inducing electronic energy transfer between the two rings, and reporting on the state mixing via its OH stretch absorptions.
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Affiliation(s)
- Evan G Buchanan
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Joseph R Gord
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
| | - Timothy S Zwier
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47907-2084, United States
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Erol A, Akalin E, Sarcan F, Donmez O, Akyuz S, Arikan CM, Puustinen J, Guina M. Excitation energy-dependent nature of Raman scattering spectrum in GaInNAs/GaAs quantum well structures. Nanoscale Res Lett 2012; 7:656. [PMID: 23190628 PMCID: PMC3552774 DOI: 10.1186/1556-276x-7-656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2012] [Accepted: 11/09/2012] [Indexed: 06/07/2023]
Abstract
The excitation energy-dependent nature of Raman scattering spectrum, vibration, electronic or both, has been studied using different excitation sources on as-grown and annealed n- and p-type modulation-doped Ga1 - xInxNyAs1 - y/GaAs quantum well structures. The samples were grown by molecular beam technique with different N concentrations (y = 0%, 0.9%, 1.2%, 1.7%) at the same In concentration of 32%. Micro-Raman measurements have been carried out using 532 and 758 nm lines of diode lasers, and the 1064 nm line of the Nd-YAG laser has been used for Fourier transform-Raman scattering measurements. Raman scattering measurements with different excitation sources have revealed that the excitation energy is the decisive mechanism on the nature of the Raman scattering spectrum. When the excitation energy is close to the electronic band gap energy of any constituent semiconductor materials in the sample, electronic transition dominates the spectrum, leading to a very broad peak. In the condition that the excitation energy is much higher than the band gap energy, only vibrational modes contribute to the Raman scattering spectrum of the samples. Line shapes of the Raman scattering spectrum with the 785 and 1064 nm lines of lasers have been observed to be very broad peaks, whose absolute peak energy values are in good agreement with the ones obtained from photoluminescence measurements. On the other hand, Raman scattering spectrum with the 532 nm line has exhibited only vibrational modes. As a complementary tool of Raman scattering measurements with the excitation source of 532 nm, which shows weak vibrational transitions, attenuated total reflectance infrared spectroscopy has been also carried out. The results exhibited that the nature of the Raman scattering spectrum is strongly excitation energy-dependent, and with suitable excitation energy, electronic and/or vibrational transitions can be investigated.
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Affiliation(s)
- Ayse Erol
- Physics Department, Science Faculty, Istanbul University, Istanbul, 34134, Turkey
| | - Elif Akalin
- Physics Department, Science Faculty, Istanbul University, Istanbul, 34134, Turkey
| | - Fahrettin Sarcan
- Physics Department, Science Faculty, Istanbul University, Istanbul, 34134, Turkey
| | - Omer Donmez
- Physics Department, Science Faculty, Istanbul University, Istanbul, 34134, Turkey
| | - Sevim Akyuz
- Physics Department, Faculty of Science and Letters, Istanbul Kultur University, Istanbul, 34156, Turkey
| | - Cetin M Arikan
- Physics Department, Science Faculty, Istanbul University, Istanbul, 34134, Turkey
| | - Janne Puustinen
- Optoelectronics Research Centre, Tampere University of Technology, Korkeakoulunkatu, Tampere, 33720, Finland
| | - Mircea Guina
- Optoelectronics Research Centre, Tampere University of Technology, Korkeakoulunkatu, Tampere, 33720, Finland
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