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The polycyclic aromatic hydrocarbon (PAH) hypothesis proposes that the aromatic infrared bands (AIBs) observed at 3.3, 6.2, 7.7, 8.6, 11.3, and 12.7 mic originate from gas-phase PAH molecules. These bands exhibit consistent peak wavelengths…

Astrophysics of Galaxies · Physics 2025-11-03 Alan T. Tokunaga , Lawrence S. Bernstein , Takashi Onaka

Decoherence is a major obstacle to any practical implementation of quantum information processing. One of the leading strategies to reduce decoherence is dynamical decoupling --- the use of an external field to average out the effect of the…

Quantum Physics · Physics 2011-07-26 Ido Almog , Yoav Sagi , Goren Gordon , Guy Bensky , Gershon Kurizki , Nir Davidson

Based on the consideration of increasing the number of initial electrons and providing an appropriate distribution of electric field strength for discharge space, a method of adopting the wire-cylindrical type electrode structure with a…

Plasma Physics · Physics 2020-08-26 Shuai Zhao , Yong Hao , Tao Qiao , Weisheng Cui

We have studied dense hydrogen and deuterium experimentally up to 320 GPa and using ab initio molecular dynamic (MD) simulations up to 370 GPa between 250 and 300 K. Raman and optical absorption spectra show significant anharmonic and…

The complex band structure of an isolated polyethylene chain is calculated within Density Functional Theory (DFT). A plane wave basis and ultrasoft pseudopotentials are used. The results are compared with those obtained via a local basis…

Materials Science · Physics 2009-11-10 Fabien Picaud , Alexander Smogunov , Andrea Dal Corso , Erio Tosatti

Recently, the production of ultrahigh-density (~10^{19}cm^{-3}) spin-polarized deuterium (SPD) atoms was demonstrated, from the photodissociation of deuterium iodide, but the upper density limit was not determined. Here, we present studies…

Polarized infrared emission from polycyclic aromatic hydrocarbons (PAHs) is important for testing the basic physics of alignment of ultrasmall grains and potentially offers a new way to trace magnetic fields. In this paper, a new model of…

Astrophysics of Galaxies · Physics 2017-12-15 Thiem Hoang

Polycyclic Aromatic Hydrocarbons (PAHs) are widely accepted as the carriers of the Aromatic Infrared Bands (AIBs), but an unambiguous identification of any specific interstellar PAH is still missing. For polar PAHs, pure rotational…

Planck results have revealed that the electric dipole emission from polycyclic aromatic hydrocarbons (PAHs) is the most reliable explanation for anomalous microwave emission that interferes with cosmic microwave background (CMB) radiation…

Astrophysics of Galaxies · Physics 2015-06-15 Thiem Hoang , A. Lazarian , P. G. Martin

The phase diagram of hydrogen is one of the most important challenges in high-pressure physics and astrophysics. Especially, the melting of dense hydrogen is complicated by dimer dissociation, metallization and nuclear quantum effect of…

Materials Science · Physics 2023-04-25 Hua Y. Geng , Q. Wu

Observations of redshifted 21cm radiation from HI at high redshifts is an important future probe of reionization. We consider the Multi-frequency Angular Power Spectrum (MAPS) to quantify the statistics of the HI signal as a joint function…

Astrophysics · Physics 2008-11-26 Kanan K. Datta , T. Roy Choudhury , Somnath Bharadwaj

The so-called aromatic infrared bands are attributed to emission of polycyclic aromatic hydrocarbons. The observed variations toward different regions in space are believed to be caused by contributions of different classes of PAH…

Astrophysics of Galaxies · Physics 2021-04-14 Shreyak Banhatti , Julianna Palotás , Pavol Jusko , Britta Redlich , Jos Oomens , Stephan Schlemmer , Sandra Brünken

Polycyclic aromatic hydrocarbons (PAHs) appear to be ubiquitous in terrestrial atmosphere as well as in the interstellar medium (ISM). In the astrophysical context presence of PAHs is interpreted by the observations of mid-IR emission bands…

Chemical Physics · Physics 2019-03-26 Rashmi Singh , Shantanu Rastogi

Total infrared fluxes are estimated for 99 HII regions around massive stars. The following wavebands have been used for the analysis: 8 and 24 $\mu$m, based on data from Spitzer space telescope (IRAC and MIPS, respectively); 70, 160, 250,…

Astrophysics of Galaxies · Physics 2018-08-15 Anastasiia Topchieva , Dmitri Wiebe , Maria S. Kirsanova

Polycyclic aromatic hydrocarbon (PAH) emission has long been proposed to be a potential star formation rate indicator, as it arises from the photodissociation region bordering the Str\"omgren sphere of young, massive stars. We apply a…

Astrophysics of Galaxies · Physics 2019-11-06 Yanxia Xie , Luis C. Ho

The influence of dispersion-less quantum optical phonons on the phase diagram of a quarter-filled Hubbard chain is studied using the Density-matrix renormalization group technique. The ground state phase diagram is obtained for frequencies…

Strongly Correlated Electrons · Physics 2009-10-31 Philippe Maurel , Marie-Bernadette Lepetit

Cyano-substituted polycyclic aromatic hydrocarbons (CN-PAHs) may contribute to the emission detected in the 7 - 9 $\mu$m (1430 - 1100 cm$^{-1}$) and 11 - 15 $\mu$m (900 - 670 cm$^{-1}$) regions of astronomical IR spectra. Anharmonic quantum…

Astrophysics of Galaxies · Physics 2024-12-10 Vincent J. Esposito , Ryan C. Fortenberry , Christiaan Boersma , Louis J. Allamandola

Small organic molecules are thought to provide building blocks for the formation of complex interstellar polycyclic aromatic hydrocarbons (PAHs). However, the underlying chemical mechanisms remain unclear, particularly concerning the role…

Astrophysics of Galaxies · Physics 2020-09-17 Meriem Hanine , Zhisen Meng , Shiru Lu , Peng Xie , Sylvain Picaud , Michel Devel , Zhao Wang

The structure and chemistry of the dusty interstellar medium (ISM) are shaped by complex processes that depend on the local radiation field, gas composition, and dust grain properties. Of particular importance are Polycyclic Aromatic…

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