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Related papers: Simulating Vibronic Spectra without Born-Oppenheim…

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A semiempirical parametric method is proposed for modeling three-dimensional (time-resolved) vibronic spectra of polyatomic molecules. The method is based on the use of the fragment approach in the formation of molecular models for excited…

Chemical Physics · Physics 2007-05-23 S. A. Astakhov , V. I. Baranov

As per the Franck-Condon principle, absorption spectroscopy reveals changes in nuclear geometry in molecules or solids upon electronic excitation. It is often assumed these changes cannot be resolved beyond the ground vibrational…

Chemical Physics · Physics 2024-01-23 Sindhana Pannir-Sivajothi , Joel Yuen-Zhou

Spectroscopy is a crucial laboratory technique for understanding quantum systems through their interactions with electromagnetic radiation. Particularly, spectroscopy is capable of revealing the physical structure of molecules, leading to…

Quantum Physics · Physics 2018-05-24 Ling Hu , YueChi Ma , Y. Xu , W. Wang , Y. Ma , K. Liu , M. -H. Yung , L. Sun

Vibrationally resolved near-edge x-ray absorption spectra at the K-edge for a number of small molecules have been computed from anharmonic vibrational configuration interaction calculations of the Franck-Condon factors. The potential energy…

Chemical Physics · Physics 2021-02-03 Torsha Moitra , Diana Madsen , Ove Christiansen , Sonia Coriani

We apply the bootstrap kernel within time dependent density functional theory to study one-dimensional chain of organic polymer poly-phenylene-vinylene and molecular crystals of picene and pentacene. The behaviour of this kernel in the…

Materials Science · Physics 2013-11-11 S. Sharma , J. K. Dewhurst , E. K. U. Gross

Vibrational spectroscopy, comprised of infrared absorption and Raman scattering spectroscopy, is widely used for label-free optical sensing and imaging in various scientific and industrial fields. The group theory states that the two…

Chemical Physics · Physics 2019-10-09 Kazuki Hashimoto , Venkata Ramaiah Badarla , Akira Kawai , Takuro Ideguchi

A mixed basis approach based on density functional theory is employed for low dimensional systems. The basis functions are taken to be plane waves for the periodic direction multiplied by B-spline polynomials in the non-periodic direction.…

Computational Physics · Physics 2015-05-20 Chung-Yuan Ren , Chen-Shiung Hsue , Yia-Chung Chang

While non-Hermitian Hamiltonians have been experimentally realized in cold atom systems, it remains an outstanding open question of how to experimentally measure their complex energy spectra in momentum space for a realistic system with…

Quantum Gases · Physics 2022-08-30 Kai Li , Yong Xu

Machine learning has emerged as an invaluable tool in many research areas. In the present work, we harness this power to predict highly accurate molecular infrared spectra with unprecedented computational efficiency. To account for…

Chemical Physics · Physics 2021-03-16 Michael Gastegger , Jörg Behler , Philipp Marquetand

In the theory of open quantum systems, spectral densities are key quantities for modeling the dynamics and spectroscopic properties of the system under investigation. In the case of light-harvesting complexes, they encode the…

Chemical Physics · Physics 2026-04-29 Sayan Maity , Tristan A. Mauck , Ulrich Kleinekathöfer

We present a comparison between Fe K-edge x-ray absorption spectra of carbonmonoxy-myoglobin and its simulation based on density-functional theory determination of the structure and vibrations and spectral simulation with…

Soft Condensed Matter · Physics 2010-08-04 G. Veronesi , C. Degli Esposti Boschi , L. Ferrari , G. Venturoli , F. Boscherini , F. D. Vila , J. J. Rehr

The presence of quantum effects in photosynthetic excitation energy transfer has been intensely debated over the past decade. Nonlinear spectroscopy cannot unambiguously distinguish coherent electronic dynamics from underdamped vibrational…

Through temporal shaping of the excitation signal, the complex-frequency scattering zeros of a lossless structure can be accessed, enabling a storage-release mechanism referred to as coherent virtual absorption. Practical demonstrations of…

The simple ultraviolet absorption spectrum of thiophene is investigated using a combination of a vibronic coupling model Hamiltonian with multi-configuration time-dependent Hartree quantum dynamics simulations. The model includes five…

Chemical Physics · Physics 2024-07-30 Michael A. Parkes , Graham A. Worth

X-ray photoemission and x-ray absorption spectroscopy are important techniques to characterize chemical bonding at surfaces and are often used to identify the strength and nature of adsorbate-substrate interactions. In this study, we judge…

Materials Science · Physics 2023-02-09 Samuel J. Hall , Benedikt P. Klein , Reinhard J. Maurer

Scattering of nonstationary electromagnetic fields from axially symmetrical bodies is numerically investigated. Simulations are performed using the time- and frequency-domain approaches. Computational results obtained for a finite perfectly…

Mathematical Physics · Physics 2007-05-23 I. G. Efimova

Mesoscopic molecular dynamics simulations are used to determine the large scale structure of several binary polymer mixtures of various chemical architecture, concentration, and thermodynamic conditions. By implementing an analytical…

Soft Condensed Matter · Physics 2010-04-05 J. McCarty , I. Y. Lyubimov , M. G. Guenza

Ultrafast chemical reactions are difficult to simulate because they involve entangled, many-body wavefunctions whose computational complexity grows rapidly with molecular size. In photochemistry, the breakdown of the Born-Oppenheimer…

Under the Franck-Condon approximation, we systematically validated the performance of density functional theory (DFT) and the effects of anharmonicity in simulating C/N/O K-edge vibrationally-resolved X-ray spectra of common diatomic…

Chemical Physics · Physics 2025-01-06 Lu Zhang , Minrui Wei , Guoyan Ge , Weijie Hua

Koopmans-compliant functionals provide an orbital-density-dependent framework for an accurate evaluation of spectral properties; they are obtained by imposing a generalized piecewise-linearity condition on the total energy of the system…

Materials Science · Physics 2022-07-06 Riccardo De Gennaro , Nicola Colonna , Edward Linscott , Nicola Marzari