Asymmetry of the Polarized-Laser-Induced Photofragmentation of Oriented C<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">H</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>I Molecules

Gandhi, Suketu R.; Curtiss, Thomas J.; Bernstein, R. B.

doi:10.1103/physrevlett.59.2951

Cited by 67 publications

(39 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[2][3][4] In these experiments, simple dipolar molecular targets are oriented before collision either by applying extremely strong electric fields during collision, 5,6 or by first selecting molecules in certain quantum states and then orienting the state-selected molecules in weak fields. [2][3][4] Large steric effects have been observed in photoionization 7 and photodissociation [8][9][10][11] and in a variety of reactive, [12][13][14][15][16][17][18][19] inelastic, 20,21 and surface collisions, [22][23][24] and the existence of steric effects is thus well documented. These systems mainly involve alkali or alkaline earth metals that react via the ''harpoon'' mechanism, whereby an electron from the easily ionized metal is used to ''harpoon'' an electropositive molecule, with the products being reeled in together by the Coulomb attraction.…”

Section: Introductionmentioning

confidence: 99%

Frontside versus backside reactivity in electron transfer to oriented tert butyl bromide and methyl bromide

Brooks

Harris

2002

The Journal of Chemical Physics

View full text Add to dashboard Cite

Electron transfer collisions between beams of neutral K atoms and neutral alkyl bromide ͑R-Br͒ molecules (RϭCH 3 ,t-C 4 H 9) are observed by detecting positive and negative ions in coincidence for energies տ4 eV, the minimum energy for overcoming the Coulomb attraction between ions. The molecules are state selected by a hexapole electric field and oriented prior to the electron transfer. The steric asymmetry for both molecules above Ϸ6 eV shows that ''frontside,'' or Br end attack, is favored to form Br Ϫ , with t-C 4 H 9 Br being more asymmetric than CH 3 Br. The asymmetry maximizes near 5 eV and as the energy decreases, apparently changes sign to favor ''backside,'' or alkyl-end attack. Free electrons ͑and K ϩ ͒ are detected from t-C 4 H 9 Br and show a similar change in preferred orientation: at low energies alkyl end attack is favored, and at high energies Br end is favored. These observations suggest that the electron is transferred into different orbitals with different spatial distributions as the energy is varied. Steric factors are evaluated from the experimental data. The steric factor for t-C 4 H 9 Br is generally smaller than for CH 3 Br and above about 5 eV, both increase with energy in Arrhenius-type dependence. The apparent ''steric activation energy'' is Ϸ2.2 eV for CH 3 Br and 3.9 eV for t-C 4 H 9 Br.

show abstract

Section: Introductionmentioning

confidence: 99%

Frontside versus backside reactivity in electron transfer to oriented tert butyl bromide and methyl bromide

Brooks

Harris

2002

The Journal of Chemical Physics

View full text Add to dashboard Cite

show abstract

“…Photodissociation can yield valuable information with regard to the orientation distribution function and has been used in the past to interpret orientational effects. 9 Recently this has been demonstrated very clearly in the ion imaging experiment of Mastenbroek et a l]0 In the present experiment a technique is used to investigate the orientation distribution function, as proposed recently for and demonstrated on NO by Van Leuken et al 8 In this technique use is made of the electric-field-induced .mixing of the initially selected upper A-doublet state with the lower doublet state, This mixing results in the appearance of "forbidden" lines in the laser-induced fluorescence (LIF) spectrum, of which the intensity is a direct measure for the mixing and consequently the orientation of the molecules. T he outline of this paper is as follows.…”

Section: Introductionmentioning

confidence: 99%

State-to-State Scattering of Oriented OH

Schreel

Meulen

1997

J. Phys. Chem. A

View full text Add to dashboard Cite

Hexapole state selection of OH molecules and subsequent orientation in an electric field is performed to study orientational effects in rotational excitation of OH in molecular collisions. Laser-induced fluorescence spectroscopy of OH is used to determine the orientational probability distribution function and to measure the cross sections for excitation. For the collisionally induced transitions of OH in the rotational ground state the steric asymmetry is determined for collisions with He, Ar, n-H2, and p-U2 (n = normal, p = para). The results show that for He excitation is preferential at the H-end of the molecule, whereas for Ar and H2 a preference for the O-end is shown in transitions to the lowest rotational states.

show abstract

“…However, Stark effects in symmetric top molecules often show nonlin-ear behavior due to hyperfine effects [21][22][23] and second-order perturbations to the Stark energy. [23][24][25] The impact of these effects on the focusing behavior 23 and opdf's [26][27][28] has been explored previously.…”

Section: Introductionmentioning

confidence: 99%