ROTATIONAL AND VIBRATIONAL INTENSITY DISTRIBUTION OF THE FIRST NEGATIVE BANDS IN SUNLIT AURORAL RAYS

1960 ◽  
Vol 38 (3) ◽  
pp. 458-476 ◽  
Author(s):  
A. Vallance Jones ◽  
D. M. Hunten
Keyword(s):  
Solar Radiation ◽  
Intensity Distribution ◽  
Thermal Equilibrium ◽  
Degrees Of Freedom ◽  
Rotational Temperature ◽  
Dissociative Recombination ◽  
Rotational Line ◽  
Kinetic Temperature ◽  
Excitation Process ◽  
Line Intensities

Spectra of sunlit auroral rays were obtained from Saskatoon during the auroras of September 3/4 and 4/5, 1958. The resolution of these spectra was sufficiently high to enable measurements to be made of the relative intensities of the lines of the 0–0 first negative [Formula: see text] band as well as the relative intensities of bands of the Δυ = −1 sequence of this system. An analysis of the rotational line intensities shows they are consistent with an excitation process in which [Formula: see text] ions in thermal equilibrium with the atmosphere at 2200 °K fluoresce under the influence of solar radiation. The vibrational intensity distribution also is consistent with a fluorescent excitation from a state of thermal equilibrium at about 2050 °K. It is shown that the results are not consistent with a fluorescent excitation process in which the rotational and vibrational degrees of freedom of the [Formula: see text] ions come into radiative equilibrium with the solar radiation. Earlier conclusions that radiative equilibrium did hold for vibration are shown to be in error as a result of the high rotational temperature and the low dispersion used. It is concluded that the destruction of [Formula: see text] ions as a result of dissociative recombination proceeds sufficiently fast to prevent any significant approach to radiative equilibrium. This investigation provides a strong indication that the kinetic temperature of a sunlit auroral ray (perhaps in the 400–500 km region) is in the neighborhood of 2000 °K. This may be somewhat higher than the temperature of the normal atmosphere at this height.

scholarly journals Investigations on a Universal Relationship Between Optical Emission and Absorption of Complex Molecules in Liquid Solutions

1999 ◽  
Vol 54 (8-9) ◽  
pp. 465-469 ◽  
Author(s):  
A. Kawski ◽  
P. Bojarski ◽  
B. Kukliński
Keyword(s):  
Fluorescence Intensity ◽  
Intensity Distribution ◽  
Thermal Equilibrium ◽  
Optical Emission ◽  
Complex Molecules ◽  
Emission Process ◽  
Vibrational Levels ◽  
Liquid Solutions ◽  
Universal Relationship ◽  
Overlapping Region

Based on a universal relationship between the extinction coefficient and the fluorescence intensity in their overlapping region, local temperatures T* higher than the ambient T were determined for short-lived luminescent molecules of lifetimes from 7 ps to 77 ps. The reason for such a local temperature T*, which holds also during the emission process, is the non-establishment of statistical equilibrium over the vibrational levels of excited molecules. It is found that the intensity distribution in the fluorescence band depends slightly on the wavelength of the excitating light, which evidences the lack of thermal equilibrium with the vicinal surrounding.

Quantum statistical physics: Functional integration formalism

2021 ◽  
pp. 64-89
Author(s):  
Jean Zinn-Justin
Keyword(s):  
Phase Space ◽  
Integral Representation ◽  
Density Matrix ◽  
Thermal Equilibrium ◽  
Degrees Of Freedom ◽  
Functional Integral ◽  
Complex Variables ◽  
Path Integral Representation ◽  
Canonical Formulation ◽  
Grand Canonical

The functional integral representation of the density matrix at thermal equilibrium in non-relativistic quantum mechanics (QM) with many degrees of freedom, in the grand canonical formulation is introduced. In QM, Hamiltonians H(p,q) can be also expressed in terms of creation and annihilation operators, a method adapted to the study of perturbed harmonic oscillators. In the holomorphic formalism, quantum operators act by multiplication and differentiation on a vector space of analytic functions. Alternatively, they can also be represented by kernels, functions of complex variables that correspond in the classical limit to a complex parametrization of phase space. The formalism is adapted to the description of many-body boson systems. To this formalism corresponds a path integral representation of the density matrix at thermal equilibrium, where paths belong to complex spaces, instead of the more usual position–momentum phase space. A parallel formalism can be set up to describe systems with many fermion degrees of freedom, with Grassmann variables replacing complex variables. Both formalisms can be generalized to quantum gases of Bose and Fermi particles in the grand canonical formulation. Field integral representations of the corresponding quantum partition functions are derived.

scholarly journals Rotational Fine Structure Lines of Interstellar C2 Toward ζ Persei

1980 ◽  
Vol 87 ◽  
pp. 263-267
Author(s):  
Frederic H. Chaffee ◽  
Barry L. Lutz ◽  
John H. Black ◽  
Paul A. Vanden Bout ◽  
Ronald L. Snell
Keyword(s):  
Fine Structure ◽  
Thermal Equilibrium ◽  
Column Density ◽  
Rotational Temperature ◽  
Detailed Model ◽  
Data Yield ◽  
Fine Structure Lines

We have detected 9 of the rotational fine structure lines of the 2-0 Phillips band of interstellar C2 toward ζ Persei using the Tull spectrograph and Reticon detector on the 2.7 m telescope at the McDonald Observatory. These data yield a total C2 column density of 1.2 × 1013 cm-2 and a rotational temperature of 97 K compared to 1.4 × 1013 cm-2 and 45 K predicted by the detailed model of the cloud by Black, Hartquist and Dalgarno. We suggest that radiative pumping through the Mulliken and Phillips systems has modified the C2 level populations in such a way as to produce an observed rotational temperature which exceeds that arising in pure thermal equilibrium.

Measurement of vibrational and rotational temperature in spark-discharge plasma by optical emission spectroscopy: Change in thermal equilibrium characteristics of plasma under air flow

2018 ◽  
Vol 20 (7) ◽  
pp. 746-757 ◽  
Author(s):  
Masao Kinoshita ◽  
Takayuki Fuyuto ◽  
Hiroshi Akatsuka
Keyword(s):  
Thermal Equilibrium ◽  
Optical Emission Spectroscopy ◽  
Discharge Plasma ◽  
Vibrational Temperature ◽  
Rotational Temperature ◽  
Air Flow ◽  
Optical Emission ◽  
Spark Discharge ◽  
Spark Plug ◽  
Spark Discharge Plasma

The vibrational and rotational temperatures in a spark-discharge plasma were measured using optical emission spectroscopy, and the influence of the air flow velocity and ambient pressure on these temperatures was investigated. The optical emissions from the plasma were led to an imaging spectroscope through an optical fiber. The temperature was estimated by fitting a theoretically calculated spectrum to that which had been acquired experimentally, formed by nitrogen molecule emission from 372 to 382 nm. The spark-discharge plasma was examined with a flow of ambient air at a discharge energy of 80 mJ. The air flow caused the spark-discharge channel to elongate downstream. At the center of the spark plug gap, the vibrational temperature in the plasma was 4000 K, whereas the rotational temperature was 2000 K. This plasma can be regarded as being in non-thermal equilibrium because the vibrational temperature was higher than the rotational temperature. At a position approximately 3 mm downstream from the spark plug gap, the vibrational and rotational temperatures increased to 4500 and 4000 K, respectively, while approaching each other. Both temperatures reached a maximum value. These results show that the plasma transitions from non-thermal equilibrium to thermal equilibrium as it is elongated by the air flow. Ignition efficiency improvements can be expected if the time required to transition from non-thermal to thermal equilibrium can be shortened.

THE ZEROTH LAW OF THERMODYNAMICS OF THE PHOTON–HYDROGEN SYSTEM AND 21 cm COSMOLOGY

2009 ◽  
Vol 18 (13) ◽  
pp. 1943-1954 ◽  
Author(s):  
LI-ZHI FANG
Keyword(s):  
Thermal Equilibrium ◽  
Neutral Hydrogen ◽  
Resonant Scattering ◽  
Hydrogen Gas ◽  
Color Temperature ◽  
Local Thermal Equilibrium ◽  
Kinetic Temperature ◽  
Hydrogen Atoms ◽  
Thermal Equilibrium State ◽  
Field Coupling

A basic physical problem of 21 cm cosmology is the so-called Wouthuysen–Field coupling, which assumes that the resonant scattering of Lyα photons with neutral hydrogen atoms will lock the color temperature of the photon spectrum around the Lyα frequency to be equal to the kinetic temperature of hydrogen gas. This assumption is actually the zeroth thermodynamic law on the formation of the local statistically thermal equilibrium state of the photon–atom system. However, the time-dependent process of approaching a local statistically thermal equilibrium with the kinetic temperature has never been studied, as it needs to solve an integral–differential equation — the radiative transfer equation of the resonant scattering. Recently, with a state-of-the-art numerical method, the formation and evolution of the Wouthuysen–Field coupling has been systematically studied. This paper reviews the physical results, including the time scales of the onset of Wouthuysen–Field coupling, the profile of frequency distribution of photons in the state of local thermal equilibrium, the effects of the expansion of the universe, the Wouthuysen–Field coupling in an optical thick halo, etc.

scholarly journals Механизм термической ионизации уротропина на поверхности интерметаллида NaAu-=SUB=-x-=/SUB=-

2022 ◽  
Vol 92 (3) ◽  
pp. 481
Author(s):  
М.В. Кнатько ◽  
М.Н. Лапушкин
Keyword(s):  
Excited State ◽  
Thermal Equilibrium ◽  
Degrees Of Freedom ◽  
Ion Current ◽  
Thermal Ionization ◽  
Adsorption Complex ◽  
Decomposition Reactions ◽  
Temperature Dependences ◽  
Monomolecular Decomposition ◽  
Bulk Structure

Thermal ionization of methenamine (C6H12N4) on the surface of the NaAux intermetallic compound has been studied. It has been established that the processes of decomposition, desorption and ionization of adsorbed compounds, thermally stimulated on the surface, proceed due to the accumulation of energy at the degrees of freedom of the adsorption complex, including the adsorbed compound and a solid, by the mechanism of monomolecular decomposition reactions. In this case, the decomposition of the adsorption complex is accompanied by the desorption of ions that are not in thermal equilibrium with the solid. The uniformity of the temperature dependences of the ion current and their distribution over two groups allowed us to conclude that ions are desorbed from the surface, which correspond to the decays of individual adsorbed molecules, as well as the decays of dimers formed on the surface. The decay of methenamine molecules during thermal ionization occurs in the same way as their decay in vacuum during electron ionization, which indicates the preservation of the bulk structure of methenamine molecules during adsorption and a significant lifetime of the excited state of compounds on NaAux.

scholarly journals Detection of New Ammonia Sources

1980 ◽  
Vol 87 ◽  
pp. 83-84
Author(s):  
G.H. Macdonald ◽  
A.T. Brown ◽  
L.T. Little ◽  
D.N. Matheson ◽  
M. Felli
Keyword(s):  
Hyperfine Structure ◽  
Molecular Hydrogen ◽  
Molecular Clouds ◽  
Column Density ◽  
Rotational Temperature ◽  
Kinetic Temperature ◽  
Excitation Temperature ◽  
Hydrogen Density

Ammonia is a favoured molecule for the study of molecular clouds since several important parameters of the cloud can be deduced from simple observations of the J,K=1,1 and 2,2 inversion doublet transitions and the hyperfine structure in the (1,1) line. With the additional knowledge of the kinetic temperature Tk from observations of CO, for example, it is possible to compute the excitation temperature of the (1,1) line (T11), the rotational temperature between the (1,1) and (2,2) levels (T21), the molecular hydrogen density n(H2) and ammonia column density N(NH3) (see, for example, Martin and Barrett, 1978).

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