Download or read book Calculated Pressure induced Vibrational Absorption in H2 H2 Collisions in Hydrogen Gas written by R. W. Patch and published by . This book was released on 1971 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Collision induced Absorption in the Rototranslational Band of H2 H2 and in the Fundamental Band and First and Second Overtone of H2 in Dense Hydrogen Gas written by Martin Andreas Abel and published by . This book was released on 2009 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: The absorption due to pairs of H2 molecules is an important opacity source in the atmospheres of various types of planets and cool stars, such as late stars, low-mass stars, brown dwarfs, certain white dwarfs, etc., and therefore of special astronomical interest [13]. The emission spectra of cool white dwarf stars differ signicantly from the expected blackbody spectra of the cores, due to collision-induced absorption by collisional complexes of hydrogen and helium in the stellar atmospheres. In order to model the radiative processes in these atmospheres, which have temperatures of several thousand kelvin, one needs accurate knowledge of the induced dipole and potential energy surfaces of collisional complexes such as H2-H2. These come from quantum-chemical calculations with the H2 bonds stretched or compressed far from equilibrium length. Since no measurements of the collision-induced absorption for these high temperatures exist, one has to undertake ab initio calculations which take into account the high vibrational excitations of the hydrogen molecules. However, before one attempts to proceed to higher temperatures where no laboratory measurements exist it is good to know that the formalism is correct and reproduces the results at temperatures where measurements exist. Therefore, in order to make sure that the calculations are reliable one compares the results of the calculations with existing laboratory measurements where possible before proceeding to higher temperatures. Molecular hydrogen has always played a special role in the collision-induced spectroscopies. The rotational transition frequencies of H2 are widely separated so that translational, rotational and vibrational induced spectral bands can be studied separately. Moreover, the H2 molecule has a small anisotropy of the intermolecular interactions which may often be ignored in first order approximations. In general hydrogen gas is a mixture of para- and ortho-hydrogen. Para-hydrogen at sufficiently low temperature is not rotationally excited and is therefore an isotropic system. However, the anisotropy can be turned on and of by raising and lowering the temperature, because the ratio of para- to ortho-hydrogen depends on the temperature. What is even more, roughly 90% of all the known matter in the universe is hydrogen, in the ionized, atomic or molecular states, which makes hydrogen one of the most important species in astrophysics. The hydrogen molecule is non-polar, and some of the most important spectra in the near and far infrared and microwave region are collision-induced, due to H2-H2 complexes. At the temperature of 297.5K measurements of the collision-induced absorption spectra of H2-H2 gas are reported in the frequency range from 1900 to 2260cm-1 [9]. The gas densities for these measurements ranged from 51 to 610 amagat. These measurements were compared with ab initio calculations of the absorption. For these calculations the isotropic potential approximation was used. In contrast to previous ab initio calculations [9] agreement between calculations and measured spectra is now observed over the full frequency range considered. A major difference to the earlier calculations is that in this work new dipole and potential energy surfaces were used. Furthermore, measurements exist of the fundamental band and first and second overtone of H2 in dense hydrogen gas. They have been compared with ab initio calculations based on the new method. Over the full range of frequencies considered the agreement between calculations and measurements is remarkable. This work demonstrates that the new method is capable of reproducing the measured spectra where those exist with high accuracy, and predicts reliable opacities where no laboratory measurements exist.
Download or read book NASA Technical Note written by and published by . This book was released on 1971 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Semiempirical Electric Dipole Moment and Its Derivative in H2 H2 and H2 H Collisions written by R. W. Patch and published by . This book was released on 1970 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 880 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Download or read book Monthly Catalog of United States Government Publications written by United States. Superintendent of Documents and published by . This book was released on 1971 with total page 1290 pages. Available in PDF, EPUB and Kindle. Book excerpt: February issue includes Appendix entitled Directory of United States Government periodicals and subscription publications; September issue includes List of depository libraries; June and December issues include semiannual index.
Download or read book Monthly Catalog of United States Government Publications Cumulative Index written by United States. Superintendent of Documents and published by . This book was released on 1976 with total page 1408 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Simulation Study of Three Instrument Displays to Assist in Airplane Thrust Management written by Milton D. McLaughlin and published by . This book was released on 1970 with total page 802 pages. Available in PDF, EPUB and Kindle. Book excerpt: Three displays were evaluated on a piloted simulator, each of which provided information which could be used in thrust management. The three displays were (1) rate of change of speed, (2) potential flight-path angle, and (3) potential rate of climb. Results are presented in the form of time histories, histograms, and pilot comments. The results include comparisons of flight-path and speed control and throttle activity with and without each display and pilot comments.
Download or read book Advances in Chemical Physics Volume 36 written by Ilya Prigogine and published by John Wiley & Sons. This book was released on 2009-09-08 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Advances in Chemical Physics series provides the chemical physics and physical chemistry fields with a forum for critical, authoritative evaluations of advances in every area of the discipline. Filled with cutting-edge research reported in a cohesive manner not found elsewhere in the literature, each volume of the Advances in Chemical Physics series serves as the perfect supplement to any advanced graduate class devoted to the study of chemical physics.
Download or read book Molecular Spectroscopy written by and published by Royal Society of Chemistry. This book was released on 1962 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on with total page 1386 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Molecular Spectroscopy written by R F Barrow and published by Royal Society of Chemistry. This book was released on 2007-10-31 with total page 606 pages. Available in PDF, EPUB and Kindle. Book excerpt: Specialist Periodical Reports provide systematic and detailed review coverage of progress in the major areas of chemical research. Written by experts in their specialist fields the series creates a unique service for the active research chemist, supplying regular critical in-depth accounts of progress in particular areas of chemistry. For over 80 years the Royal Society of Chemistry and its predecessor, the Chemical Society, have been publishing reports charting developments in chemistry, which originally took the form of Annual Reports. However, by 1967 the whole spectrum of chemistry could no longer be contained within one volume and the series Specialist Periodical Reports was born. The Annual Reports themselves still existed but were divided into two, and subsequently three, volumes covering Inorganic, Organic and Physical Chemistry. For more general coverage of the highlights in chemistry they remain a 'must'. Since that time the SPR series has altered according to the fluctuating degree of activity in various fields of chemistry. Some titles have remained unchanged, while others have altered their emphasis along with their titles; some have been combined under a new name whereas others have had to be discontinued. The current list of Specialist Periodical Reports can be seen on the inside flap of this volume.
Download or read book Nuclear Science Abstracts written by and published by . This book was released on 1976 with total page 680 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications of the National Bureau of Standards Catalog written by United States. National Bureau of Standards and published by . This book was released on 1987 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Cumulative Title Index to United States Public Documents 1789 1976 written by Daniel W. Lester and published by . This book was released on 1979 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Publications of the National Institute of Standards and Technology Catalog written by National Institute of Standards and Technology (U.S.) and published by . This book was released on 1988 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Energy Research Abstracts written by and published by . This book was released on 1985 with total page 780 pages. Available in PDF, EPUB and Kindle. Book excerpt:
