Rotational and vibrational energy transfer in vibrationally excited acetylene at energies near 6560 cm−1

Han, Jiande; Freel, Keith; Heaven, Michael C.

doi:doi:10.1063/1.3671459

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Ab initio calculations of the electronic states of AsH₂ including dissociation characteristics

Multireference configuration interaction calculations have been carried out for low-lying electronic states of AsH2. Bending potentials for the ten lowest states of AsH2 are obtained in C2v symmetry for As–H distances fixed at the the ground state equilibrium value of 2.845 a0, as well as for the minimum energy path constrained to R1 = R2. The calculated equilibrium geometries for the 2B1 ground state and the 2A1 excited state agree very well with the previous experimental and theoretical result...

HNO₃−NH_x, H₂SO₄−NH_x, CH(O)OH−NH_x, and CH₃C(O)OH−NH_x complexes and their role in the formation of condensation nuclei

The formation of sulfuric acid (H2SO4), nitric acid (HNO3), acetic acid (CH3C(O)OH), and formic acid (HC(O))H) complexes with ammonia (NH3), amidogen radical (NH2), and imidogen radical (NH) was studied using natural bond orbital calculations. The equilibrium structures, binding energies, and harmonic frequencies were calculated for each acid-NHx complex using hybrid density functional (B3LYP) and second-order Møller-Plesset perturbation approximation methods with the 6-311++G(3df,3pd) basis set...

Collisional energy transfer kinetics of vibrationally excited acetylene has been examined for states with internal energies near 6560 cm⁻¹. Total population removal rate constants were determined for selected rotational levels of the (1,0,1,0⁰,0⁰) and (0,1,1,2⁰,0⁰) states. Values in the range of (10–18) × 10⁻¹⁰ cm³ s⁻¹ were obtained. Measurements of state-to-state rotational energy transfer rate constants were also carried out for these states. The rotational energy transfer kinetics was found to be consistent with simple energy gap models for the transfer probabilities. Vibrational transfer out of the (0,1,1,2⁰,0⁰) state accounted for no more than 16% of the total removal process. Transfer from (1,0,1,0⁰,0⁰) to the u-symmetry (0,2,0,3¹,1⁻¹), (0,1,1,2⁰,0⁰), and (1,1,0,1¹,1⁻¹) states was observed. Applying the principle of detailed balance to these data indicated that vibrational transfer to (1,0,1,0⁰,0⁰) accounted for ∼0.1% of the population loss from (0,2,0,3¹,1⁻¹) or (0,1,1,2⁰,0⁰), and 3% of the loss from (1,1,0,1¹,1⁻¹). Relative rotational transfer probabilities were obtained for transfer to the g-symmetry (1,1,0,2⁰,0⁰)/(0,0,2,0⁰,0⁰) dyad. These results are related to recent studies of optically pumped acetylene lasers.

Article Outline

INTRODUCTION
1. Spectroscopic notation and background
EXPERIMENTAL
RESULTS AND ANALYSIS
1. Rotational transfer kinetics of the (0,1,1,2 ⁰ _, 0 ⁰ ) state
2. Rotational transfer kinetics of the (1,0,1,0 ⁰ ,0 ⁰ ) state
3. Vibrational energy transfer
KINETIC MODELING
1. Rotational energy transfer
2. Rotation-vibration energy transfer
DISCUSSION

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KEYWORDS and PACS

Keywords

excited states, molecule-photon collisions, optical pumping, organic compounds, probability, rotational states, vibrational states

PACS

33.15.Mt

Rotation, vibration, and vibration-rotation constants
33.80.Be

Level crossing and optical pumping
31.15.vj

Electron correlation calculations for atoms and ions: excited states

ARTICLE DATA

Digital Object Identifier

http://dx.doi.org/10.1063/1.3671459

PUBLICATION DATA

ISSN

0021-9606 (print)

1089-7690 (online)

Publisher

$abstract.society.value is a Member of CrossRef

American Institute of Physics

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