Molecular astrophysics

The dense clouds mentioned in the first paragraph cannot be investigated by means of the X 21 cm line, or any optical transition, but only by means of molecular lines in the radio frequency range. This is why interstellar molecules are so important in modern astrophysics. Molecular lines contain much information on the physical state of these dense and cool clouds. Moreover, the abundance of interstellar molecules itself can shed light on the physical conditions, including the radiation field in dense clouds, once we more fully understand... 

CfA (Harvard-Smithsonian Center for Astrophysics) Molecular databases. http //cfa-www.harvard.edu/amdata/ampdata/amdata.shtml. Accessed 21 June 2012... 

The astrochemistty of ions may be divided into topics of interstellar clouds, stellar atmospheres, planetary atmospheres and comets. There are many areas of astrophysics (stars, planetary nebulae, novae, supemovae) where highly ionized species are important, but beyond the scope of ion chemistry . (Still, molecules, including H2O, are observed in solar spectra [155] and a surprise in the study of Supernova 1987A was the identification of molecular species, CO, SiO and possibly ITf[156. 157]. ) In the early universe, after expansion had cooled matter to the point that molecules could fonn, the small fraction of positive and negative ions that remained was crucial to the fomiation of molecules, for example [156]... 

Dalgarno A and Lepp S 1996 Applications of atomic and molecular physics to astrophysics Atomic, Moiecuiar, and Opticai Physics Handbook ed G W F Drake (Woodbury, NY AlP)... 

A microwave pulse from a tunable oscillator is injected into the cavity by an anteima, and creates a coherent superposition of rotational states. In the absence of collisions, this superposition emits a free-mduction decay signal, which is detected with an anteima-coupled microwave mixer similar to those used in molecular astrophysics. The data are collected in the time domain and Fourier transfomied to yield the spectrum whose bandwidth is detemimed by the quality factor of the cavity. Hence, such instruments are called Fourier transfomi microwave (FTMW) spectrometers (or Flygare-Balle spectrometers, after the inventors). FTMW instruments are extraordinarily sensitive, and can be used to examine a wide range of stable molecules as well as highly transient or reactive species such as hydrogen-bonded or refractory clusters [29, 30]. 

Hartquist T W and Williams D A (eds) 1998 The Molecular Astrophysics of Stars and Galaxies (Oxford Oxford University Press)... 

Quantum Chemistry. From Molecular Astrophysics to Molecular Engineering. 1996 ISBN 0-7923-3837-5... 

Figure 5.24 Glycine spectra (at 1 MHz resolution) observed at 206,468 MHz (line 21) in (a) Sgr B2(N-LMH), (b) Orion KL, and (c) W51 el/e2 and at 240,899 MHz (line 26) in (d) Sgr B2(N-LMH), (e) Orion KL, and (f) W51 el/e2. The abscissae give the rest frequencies based on the assumed LSR velocities 64.0, 8.0, and 60.0 km s 1 for Sgr B2(N-LMH), Orion KL, and W51 el/e2, respectively. The thick vertical lines mark the glycine lines at the frequencies corresponding to the measured velocities. The thin vertical lines denote the spectral features of other molecular species question marks indicate uncertain identifications because of overly strong line intensities or inconsistent LSR velocities. (Reproduced from the Astrophysical Journal 593 848-867, 2003 by permission of the AAS)...

W.C. Martin, Sources of Atomic Spectroscopy Data for Astrophysics , in PL. Smith and W. L. Wiese (eds.), Atomic and Molecular Data for Space Astronomy Needs, Analysis and Availability, Springer, Berlin, 1992. 

Eric J. Heller, Institute for Theoretical Atomic and Molecular Physics, Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts, U.S.A. Robin M. Hochstrasser, Department of Chemistry, The University of Pennsylvania, Philadelphia, Pennsylvania, U.S.A. 

Lada, C. J. and Lada, E. A. (2003) Embedded clusters in molecular clouds. Annual Reviews of Astronomy and Astrophysics, 41, 57—115. 

Supermolecular spectra could perhaps be studied with state-selection using adequate molecular beam techniques. That would not be easy, however, because of the smallness of the dipole moments induced by in-termolecular interactions. For the purpose of this book, we will mostly deal with bulk spectra, or interaction-induced absorption of pure and mixed gases. A great variety of excellent measurements of such spectra exists for a broad range of temperatures, while state-selected supermolecular absorption beam data are virtually non-existent at this time. Furthermore, important applications in astrophysics, etc., are concerned precisely with the optical bulk properties of real gases and mixtures. 

Measurements of collision-induced spectra reflect certain details about intermolecular interactions. If analyzed with care, such information will enhance knowledge of molecular interactions. Furthermore, for specific applications, laboratory measurements of collision-induced spectra taken at a few fixed temperatures must be interpolated, often even extrapolated to the temperatures of interest. We will, therefore, discuss the tools available for analysis and further use of laboratory measurements, for example, for astrophysical applications. 

F. Palla. Low-temperature Rosseland mean opacities for zero-metal gas mixtures. In G. H. F. Diercksen, W. F. Huebner, and P. W. Langhoff, eds., Molecular Astrophysics - State of the Art and Future Directions, p. 687, D. Reidel, Dordrecht, 1985. 

Utilization of data obtained from various plasma sources (e.g. beam-foil, tokamak and laser-produced plasma [287]) enabled the identification with high accuracy of the lines of highly ionized atoms in solar spectra. A special commision No 14 on Atomic and Molecular Data of the International Astronomical Union coordinates the activity on systematization of spectroscopic data, informs the astrophysics community on new developments and provides assessments and recommendations. It also provides reports which highlight these new developments and list all important recent literature references on atomic spectra and wavelength standards, energy level analyses, line classifications, compilations of laboratory data, databases and bibliographies. 

Vidali G, Roser JE, Manico G, Pirronello V (2002). In Farid Salama (ed) Investigation of formation of molecular hydrogen on dust grain analogues. NASA Laboratory Astrophysics Workshop, Book of Abstracts of the NASA LAW held in NASA-Ames Research Center, Moffett Field, California, May 1-3, 2002 Wada S, Kaito C, Kimura S, Tokunaga AT (1999) Adv Space Res 24 523 Xianwei S, Jackson B (2002) Surface Sci 496 318... 

The interpretation of the intensities of lines observed in astrophysical sources requires a wide variety of reliable atomic and, to a lesser extent, molecular data [1]. Also, the steady development of high temperature plasmas, in relation to the fusion programmes ongoing in several countries, has given rise to a considerable interest in the spectroscopy ofheavy and/or highly ionised atoms [2], The spectacular advance of some experimental techniques has not diminished the need for reliable theoretical data. In the production of spectroscopic quantities such as oscillator strengths to fulfill the present demands of both the astrophysics and plasma physics communities, several authors [3-5] have emphasised the need for both experimentalists and theoreticians to self-assess the data they supply. 

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