Effect of multiple encounters on vibrational to translational energy transfer

1994 ◽  
Vol 72 (3) ◽  
pp. 484-491 ◽  
Author(s):  
Neil Snider
Keyword(s):  
Energy Transfer ◽  
Vibrational Energy ◽  
Average Energy ◽  
Harmonic Oscillators ◽  
Relative Mass ◽  
Translational Energy ◽  
Fixed Temperature ◽  
Final Energy ◽  
Wide Range ◽  
Morse Oscillators

Vibrational to translational energy transfer was studied computationally and analytically for collinear, impulsive collisions with square well oscillators, harmonic oscillators, and Morse oscillators. At a fixed temperature T the average number of encounters is between one and two if the vibrational energy EV is large compared to kT and (or) if the relative mass of the collider is small. If these conditions are met, [Formula: see text] the average energy transferred per collision, varies nearly linearly with EV over a wide range. If the average number of encounters is greater than two, [Formula: see text] as a function of EV has a more complicated form. The average final energy, [Formula: see text] is less than what is predicted by the single encounter impulsive collision (SEI) model. Other things being equal, the ratio of the actual average final energy to the SEI average final energy is roughly the same for all of the above mentioned oscillators.

Kinetic Study of Vibrational Energy Transfer from a Wide Range of Vibrational Levels of O2(X3Σg−,v= 6−12) to CF4†

2008 ◽  
Vol 112 (39) ◽  
pp. 9290-9295 ◽  
Author(s):  
Shinji Watanabe ◽  
Hidekazu Fujii ◽  
Hiroshi Kohguchi ◽  
Takayuki Hatano ◽  
Ikuo Tokue ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Kinetic Study ◽  
Vibrational Energy ◽  
Vibrational Energy Transfer ◽  
Wide Range ◽  
Vibrational Levels

Energy transfer in the quenching of singlet molecular oxygen - III. Application of statistical theory

1977 ◽  
Vol 356 (1686) ◽  
pp. 307-314 ◽  
Keyword(s):  
Statistical Theory ◽  
Energy Transfer ◽  
Energy Distribution ◽  
Molecular Oxygen ◽  
Vibrational Energy ◽  
Vibrational Excitation ◽  
Translational Energy ◽  
Singlet Molecular Oxygen ◽  
Vibrational Energy Distribution

The vibrational energy distribution in molecules which have quenched O 2 ( 1 ∑ + g ) to O 2 ( 1 ∆ g ) or O 2 ( 1 ∆ g ) to O 2 ( 3 ∑ - g ) is interpreted in terms of the statistical theory. This theory is extended to include cases where initial rotational and translational energy contributes to vibrational excitation of the products. A common linear surprisal plot is observed in the quenching both of O 2 ( 1 ∑) and O 2 ( 1 ∆) by a number of molecules. Strongly inverted vibrational distributions with ⋋ v = - 7.5 are inferred for both products of the quenching step.

scholarly journals Vibrational Energy Transfer in CO+N2 Collisions: A Database for V–V and V–T/R Quantum-Classical Rate Coefficients

Molecules ◽  
2021 ◽  
Vol 26 (23) ◽  
pp. 7152
Author(s):  
Qizhen Hong ◽  
Massimiliano Bartolomei ◽  
Cecilia Coletti ◽  
Andrea Lombardi ◽  
Quanhua Sun ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Rate Constants ◽  
Potential Energy Surfaces ◽  
Vibrational Energy ◽  
Classical Method ◽  
Rate Coefficients ◽  
Collision Dynamics ◽  
Aerospace Applications ◽  
Wide Range ◽  
Experimental Values

Knowledge of energy exchange rate constants in inelastic collisions is critically required for accurate characterization and simulation of several processes in gaseous environments, including planetary atmospheres, plasma, combustion, etc. Determination of these rate constants requires accurate potential energy surfaces (PESs) that describe in detail the full interaction region space and the use of collision dynamics methods capable of including the most relevant quantum effects. In this work, we produce an extensive collection of vibration-to-vibration (V–V) and vibration-to-translation/rotation (V–T/R) energy transfer rate coefficients for collisions between CO and N2 molecules using a mixed quantum-classical method and a recently introduced (A. Lombardi, F. Pirani, M. Bartolomei, C. Coletti, and A. Laganà, Frontiers in chemistry, 7, 309 (2019)) analytical PES, critically revised to improve its performance against ab initio and experimental data of different sources. The present database gives a good agreement with available experimental values of V–V rate coefficients and covers an unprecedented number of transitions and a wide range of temperatures. Furthermore, this is the first database of V–T/R rate coefficients for the title collisions. These processes are shown to often be the most probable ones at high temperatures and/or for highly excited molecules, such conditions being relevant in the modeling of hypersonic flows, plasma, and aerospace applications.

scholarly journals Melt-Spun Photoluminescent Polymer Optical Fibers for Color-Tunable Textile Illumination

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1740
Author(s):  
Konrad Jakubowski ◽  
Manfred Heuberger ◽  
Rudolf Hufenus
Keyword(s):  
Energy Transfer ◽  
Optical Fibers ◽  
Color Space ◽  
Emission Spectra ◽  
Wide Range ◽  
Color Tunable ◽  
Melt Spun ◽  
Polymer Optical Fibers ◽  
Collective Emission ◽  
Down Conversion

The increasing interest in luminescent waveguides, applied as light concentrators, sensing elements, or decorative illuminating systems, is fostering efforts to further expand their functionality. Yarns and textiles based on a combination of distinct melt-spun polymer optical fibers (POFs), doped with individual luminescent dyes, can be beneficial for such applications since they enable easy tuning of the color of emitted light. Based on the energy transfer occurring between differently dyed filaments within a yarn or textile, the collective emission properties of such assemblies are adjustable over a wide range. The presented study demonstrates this effect using multicolor, meltspun, and photoluminescent POFs to measure their superimposed photoluminescent emission spectra. By varying the concentration of luminophores in yarn and fabric composition, the overall color of the resulting photoluminescent textiles can be tailored by the recapturing of light escaping from individual POFs. The ensuing color space is a mean to address the needs of specific applications, such as decorative elements and textile illumination by UV down-conversion.

scholarly journals Time-Resolved Measurements and Master Equation Modelling of the Unimolecular Decomposition of CH3OCH2

2020 ◽  
Vol 234 (7-9) ◽  
pp. 1233-1250 ◽  
Author(s):  
Arrke J. Eskola ◽  
Mark A. Blitz ◽  
Michael J. Pilling ◽  
Paul W. Seakins ◽  
Robin J. Shannon
Keyword(s):  
Energy Transfer ◽  
Master Equation ◽  
Rate Coefficient ◽  
Zero Point ◽  
Buffer Gas ◽  
Unimolecular Decomposition ◽  
Time Resolved ◽  
Point Energy ◽  
Wide Range ◽  
Transfer Parameters

AbstractThe rate coefficient for the unimolecular decomposition of CH3OCH2, k1, has been measured in time-resolved experiments by monitoring the HCHO product. CH3OCH2 was rapidly and cleanly generated by 248 nm excimer photolysis of oxalyl chloride, (ClCO)2, in an excess of CH3OCH3, and an excimer pumped dye laser tuned to 353.16 nm was used to probe HCHO via laser induced fluorescence. k1(T,p) was measured over the ranges: 573–673 K and 0.1–4.3 × 1018 molecule cm−3 with a helium bath gas. In addition, some experiments were carried out with nitrogen as the bath gas. Ab initio calculations on CH3OCH2 decomposition were carried out and a transition-state for decomposition to CH3 and H2CO was identified. This information was used in a master equation rate calculation, using the MESMER code, where the zero-point-energy corrected barrier to reaction, ΔE0,1, and the energy transfer parameters, ⟨ΔEdown⟩ × Tn, were the adjusted parameters to best fit the experimental data, with helium as the buffer gas. The data were combined with earlier measurements by Loucks and Laidler (Can J. Chem.1967, 45, 2767), with dimethyl ether as the third body, reinterpreted using current literature for the rate coefficient for recombination of CH3OCH2. This analysis returned ΔE0,1 = (112.3 ± 0.6) kJ mol−1, and leads to $k_{1}^{\infty}(T)=2.9\times{10^{12}}$ (T/300)2.5 exp(−106.8 kJ mol−1/RT). Using this model, limited experiments with nitrogen as the bath gas allowed N2 energy transfer parameters to be identified and then further MESMER simulations were carried out, where N2 was the buffer gas, to generate k1(T,p) over a wide range of conditions: 300–1000 K and N2 = 1012–1025 molecule cm−3. The resulting k1(T,p) has been parameterized using a Troe-expression, so that they can be readily be incorporated into combustion models. In addition, k1(T,p) has been parametrized using PLOG for the buffer gases, He, CH3OCH3 and N2.

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