Energy Transfer by Collisions in Vapors of Chlorinated Methanes

Sette, D.; Busala, A.; Hubbard, J. C.

doi:10.1063/1.1742123

Cited by 67 publications

(21 citation statements)

References 13 publications

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“…A Brillouin scattering experiment, originally designed to measure the pressure dependence of the relaxation time z, enabled the author to determine the probability of energy transfer in liquid CC14 at 25 ~ [4]. This result, together with data on the ultrasonic velocity dispersion in gaseous CC14 at pressures of a few mm Hg [5,6] will be used to investigate the validity of Eq. (1) for this chemical compound.…”

Section: /T) Exp (-E/k T)mentioning

confidence: 99%

Collisional transition probability in gaseous and liquid carbontetrachloride

Sedlacek

1975

Z Physik A

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Abstract.In gaseous CC14 at 20 to 30 ~ the probability that a binary collision effects an energy transfer between the translational and the vibrational degrees of freedom is 3.8.10 -3, in liquid CC14 at the same temperature it is close to 2.6-10 -3. The ratio of these experimental values corresponds exactly to that predicted from the theoretical /T). exp (-e/k T).For a large number of gases and liquids the excess of sound absorption over its "classical" value (mainly determined by the shear viscosity) is due to the vibrational specific heat (Ci) of the molecules [1]. The relaxation time (r) of Ci depends upon the number of binary collisions a molecule undergoes per unit time (F) and the probability (P) that such a collision effects an energy transfer between the translational and the vibrational degrees of freedom: ~ = (F. P)-1. Because of the effect of the long range attractive forces, the collisional transition probability in a gas of moderate density is higher than in a highly compressed gas or in a liquid of the same chemical composition. The ratio of Pliquid to Pgas is given by a relationship which has been derived by Litovitz from the isolated binary collision theory for the vibrational relaxation [-2, 3] :

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Section: /T) Exp (-E/k T)mentioning

confidence: 99%

Collisional transition probability in gaseous and liquid carbontetrachloride

Sedlacek

1975

Z Physik A

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“…12) j 1 + IWTj where T. is the relaxation time of the j th energy transfer and C. is the specific heat associated with it. (3)(4) and CHgClg (32) vlti where C m is the specific heat associated with the exchange mode. Where more than one relaxation time is observed the C ^ is replaced by the total specific heat of the modes relaxing through each exchange mode.…”

Section: Discussionmentioning

confidence: 99%

Sound Dispersion in Binary Mixtures of Halomethane Gases

Boade

Legvold

1965

The Journal of Chemical Physics

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Sound dispersion has been experimentally examined in all binary combinations of the halomethane gases, CH2F2, CHF3, CF4, CCl2F2, and CHCl2F. Concentrations of 25%, 50%, and 75% were examined in each combination. The experimentally determined vibrational relaxation time of each mixture was related to the equation τ−1=X2τAA−1+(1—X )2τBB−1+X(1—X) (τAB−1+τBA−1). A single relaxation time was observed in all the mixtures, and the above equation was found to be valid when the relaxation times of the individual gases in the mixture were similar and when their vibrational specific heats were similar. Values of (τAB−1+τBA−1) were deduced from the data and compared with values calculated from an extended version of the Schwartz, Slawsky, and Herzfeld theory. A Lennard-Jones 7–28 interaction potential was used for the calculations and appears to be an appropriate potential for these molecules.

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“…Apart from sulfur dioxide, gaseous dichloromethane, CH 2 Cl 2 , also exhibits a marked double-dispersion curve. 29 From a plot of v( f ) 2 vs. log(f/P) at 303.15 K, the relaxation frequencies f 00…”

Section: Introductionmentioning

confidence: 99%