Simple quasi-accommodation model of vibrational energy transfer. Low-pressure thermal methyl isocyanide isomerization
01 Aug 1970-The Journal of Physical Chemistry (American Chemical Society)-Vol. 74, Iss: 17, pp 3151-3159
About: This article is published in The Journal of Physical Chemistry.The article was published on 1970-08-01. It has received 76 citations till now. The article focuses on the topics: Methyl isocyanide & Isomerization.
Citations
More filters
TL;DR: In this paper, a relationship is developed from two distinct theoretical approaches to correlate the rate constants kM or cross sections σM for a series of added gases M which collisionally induce a state transformation A*→B.
Abstract: A relationship is developed from two distinct theoretical approaches to correlate the rate constants kM or cross sections σM for a series of added gases M which collisionally induce a state transformation A*→B. The correlation derived from theory is where C is a constant and eA*M is the intermolecular well depth between A* and M. We observe that experimental data can be described by a related correlation where β is a constant and eMM is the well depth between pairs of M molecules. This correlation is shown to be general. It works for electronic state deactivation in atoms, intersystem crossing and internal conversion in S1 polyatomics, rotational and also vibrational relaxation in S1 polyatomics, predissociation in diatomics and polyatomics, and vibrational relaxation in a free radical as well as in a molecular ion. The theory is appropriate only when attractive forces dominate the interaction, and this seems consistent with the experimental data. The correlation thus provides a simple means to distinguis...
166 citations
TL;DR: In this article, the average energy transferred per collision, which can depend on the vibrational excitation energy E of the azulene, was investigated using infrared fluorescence detection, and two methods were used to obtain ǫ(E) values from the fluorescence decay curves.
Abstract: Collisional deactivation of highly vibrationally excited azulene in the electronic ground state was investigated using infrared fluorescence detection. Azulene (S0, E) was prepared with E≂17 500 cm−1 and E≂30 600 cm−1 by laser excitation at 600 and 337 nm, respectively. Advantage was taken of the fast internal conversion rate to S0 azulene from S1(600 nm) and S2(337 nm) electronic states. The collider gases investigated are He, Ne, Ar, Kr, Xe, H2, D2, N2, CO, O2, CO2, H2O, NH3, CH4, SF6, n‐C4H10, and unexcited azulene. The results are expressed in terms of 〈ΔE(E)〉, the average energy transferred per collision, which can depend on the vibrational excitation energy E of the azulene. Using previously obtained knowledge of the dependence of infrared fluorescence intensity on E [M. J. Rossi and J. R. Barker, Chem. Phys. Lett. 85, 21 (1982)], two methods were used to obtain 〈ΔE(E)〉 values from the fluorescence decay curves: (1) an approximate method that considered only the average energy, and (2) solution of t...
152 citations
TL;DR: In this article, the stepwise deactivation of the excited azulene molecules in collisions with a variety of 23 inert bath gases was monitored by time-resolved hot UV absorption spectroscopy at 290 nm.
Abstract: Vibrationally highly excited azulene molecules in the electronic ground state (excitation energy 〈E〉=30 600 cm−1) were produced by excitation with a N2 laser. The stepwise deactivation of the excited molecules in collisions with a variety of 23 inert bath gases was monitored by time‐resolved hot UV absorption spectroscopy at 290 nm. Using previously determined calibration curves of the absorption coefficient at 290 nm as a function of the excitation energy 〈E〉, energy‐loss curves 〈E(t)〉 were recorded and analyzed with respect to the average energies 〈ΔE〉 transferred per collision. The dependencies of 〈ΔE〉 on the excitation energy 〈E〉 were derived. In most cases, 〈ΔE〉 was found to be only weakly dependent on 〈E〉 above 10 000 cm−1, whereas a stronger rise with energy became apparent only at lower energies. A comparison with earlier IR emission experiments on the azulene system is given.
123 citations
TL;DR: In this paper, the average energies transferred per collision for a series of bath gases were determined, for a given bath gas, to increase very slightly with the size of the excited molecule.
Abstract: Vibrationally highly excited ethyl‐cycloheptatriene (41 600 cm−1) and isopropyl‐cycloheptatriene (41 800 cm−1) molecules in the electronic ground state have been prepared by UV laser excitation inducing one‐photon absorption and subsequent internal conversion. Collisional energy loss of these molecules has been followed directly by hot UV absorption spectroscopy. Average energies transferred per collision 〈ΔE〉 have been determined for a series of bath gases. 〈ΔE〉 values were found, for a given bath gas, to increase very slightly with the size of the excited molecule.
94 citations
TL;DR: In this paper, a review of the application of time-resolved infrared fluorescence technique and its application to studies of the deactivation of highly vibrationally excited benzene-d0, benzened6, toluene-D0, and toluen-d8 is presented.
Abstract: This paper reviews the time-resolved infrared fluorescence technique and its application to studies of the deactivation of highly vibrationally excited benzene-d0, benzene-d6, toluene-d0, and toluene-d8 The energy transfer parameters obtained are summarized in terms of both «ΔE» and d, the average total energy transferred per collision and the average energy transferred in deactivating collisions, respectively The mechanisms of energy transfer have also been investigated to determine the roles of vibration-to-translation/rotation and vibration-to-vibration energy transfer and the possible influence of quantum effects The review concludes with a brief summary of a current view of large molecule energy transfer and suggestions for future work
92 citations