Structure and dynamics of higher vibronic levels in the methyl radical Rydberg 3s state

Westre, S. G.; Gansberg, T. E.; Kelly, Peter B.; Ziegler, L. D.

doi:10.1021/j100188a012

Cited by 26 publications

(27 citation statements)

References 2 publications

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“…These results are quite close to the experimental value of 5.74 eV. 37 The adiabatic excitation energies to the 3p 2 A 2 ′′ state at the MR-CISD and MR-CISD+Q levels are 7.02 and 7.22 eV, in quite good agreement with the experimental value of 7.45 eV. 38 The adiabatic ionization energy of 9.66 eV for CH 3 at the MR-CISD+Q level compares well with the experimental value of 9.84 eV.…”

Section: Resultssupporting

confidence: 91%

Multireference CI Study of Excitation Energies and Potential Energy Surfaces of CH₃F

Bauerfeldt

Lischka

2004

J. Phys. Chem. A

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Vertical excitation energies for the eight singlet-excited electronic states 1 1 E (2e f 3s), 2 1 E (2e f 3p a1) , 3 1 E (2e f 3p e ), 2 1 A 1 (2e f 3p e ), 1 1 A 2 (2e f 3p e ), 3 1 A 1 (2p a1 f 3s), 4 1 A 1 (2p a1 f 3p a1 ), and 4 1 E (2p a1 f 3p e ) of CH 3 F were investigated using the SA-MCSCF, MR-CISD, and MRCISD+Q approaches. Our results mostly confirm the experimental assignments but suggest some modifications for the main contribution to the maximum observed in the range from 12.5-14 eV. The dissociation channels for the production of fluorine atoms have been characterized. Potential energy curves for the dissociation of the CF bond under C 3V symmetry restrictions were computed for all states mentioned above leading to the ground-state dissociation channel CH 3 (X ˜2A 2 ′′) + F( 2 P), the excited-state channels CH 3 (3s 2 A 1 ′) + F( 2 P) and CH 3 (3p 2 A 2 ′′) + F( 2 P) and also to the ionic limit CH 3 + ( 1 A 1 ′) + F -( 1 S). All curves except the one for the ionic state show repulsive behavior. The search for a global minimum for the ionic state led to the structure H 2 CH + Fin the 3 1 A′ state. It is strongly bound by 5.67 eV with respect to the ionic dissociation limit of F -+ CH 3 + . † Part of the special issue "Fritz Schaefer Festschrift".

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Section: Resultssupporting

confidence: 91%

Multireference CI Study of Excitation Energies and Potential Energy Surfaces of CH₃F

Bauerfeldt

Lischka

2004

J. Phys. Chem. A

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“…The rovibrational dependence of predissociation rate of the 3s Rydberg state of the methyl radical was investigated by resonance enhanced Raman spectroscopy by Westre et al 15,16 and in this state the lifetime of CD 3 was found to halve upon with one quantum of excitation in the umbrella mode, ν 2 . In ref 16 , rotation-dependent subpicosecond lifetimes were obtained with a smooth J dependence.…”

Section: Introductionmentioning

confidence: 99%

“…Theoretical studies on the predissociation dynamics of the methyl radical are very scarce 16,20,21 In the work of Yu et al 20 , a small basis set RHF calculation was performed to obtain semiquantitative information about the relative barrier heights of radical (CH 3 → CH 2 + H) and molecular (CH 3 → CH + H 2 ) predissociation pathways from the ground, 3s and 3p states of the methyl radical. The group also used calculated relative energies of products and concluded that at the excitation energy of the 3p z state, it is thermodynamically possible to form theX 3 B 1 , 1 1 A 1 , 1 1 B 1 and 2 1 A 1 states of CH 2 as the product of radical predissociation, and CH(A 2 ∆) and CH(X) as products of molecular predissociation.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond predissociation dynamics of the methyl radical from the 3p_z Rydberg state

Balerdi

Woodhouse

Zanchet

et al. 2016

Phys. Chem. Chem. Phys.

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“…Westre and co-workers12,13 investigated the predissociation dynamics of the 3s Rydberg state for CH 3 and CD 3 radicals using resonance enhanced Raman spectroscopy. Subpicosecond lifetimes of around 90 fs for CH3 in the 000 band were estimated.…”

Section: Introductionmentioning

confidence: 99%

“…Theoretical studies on the photodissociation dynamics of methyl are very scarce13–16. Yu et al14 performed a small basis set restricted Hartree-Fock calculation followed by configuration interaction considering both single and double substitutions (RHF-CISD) in order to obtain excitation energies for excited states and to discuss the possible fragmentation pathways, CH3 → CH2 + H and CH3 → CH + H2, for the 3s and 3p Rydberg states.…”

Section: Introductionmentioning

confidence: 99%

Imaging the photodissociation dynamics of the methyl radical from the 3s and 3p_z Rydberg states

Poullain

Chicharro

Zanchet

et al. 2016

Phys. Chem. Chem. Phys.

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The photodissociation dynamics of the methyl radical from the 3s and 3pz Rydberg states have been studied using the velocity map and slice ion imaging in combination with pump-probe nanosecond laser pulses. The reported translational energy and angular distributions of the H((2)S) photofragment detected by (2+1) REMPI highlight different dissociation mechanisms for the 3s and 3pz Rydberg states. A narrow peak in the translational energy distribution and an anisotropic angular distribution characterize the fast 3s photodissociation, while for the 3pz state Boltzmann-type translational energy and isotropic angular distributions are found. High level ab initio calculations have been performed in order to elucidate the photodissociation mechanisms from the two Rydberg states and to rationalize the experimental results. The calculated potential energy curves highlight a typical predissociation mechanism for the 3s state, characterized by the coupling between the 3s Rydberg state and a valence repulsive state. On the other hand, the photodissociation on the 3pz state is initiated by a predissociation process due to the coupling between the 3pz Rydberg state and a valence repulsive state and constrained, later on, by two conical intersections that allow the system to relax to lower electronic states. Such a mechanism opens up different reaction pathways leading to CH2 photofragments in different electronic states and inducing a transfer of energy between translational and internal modes.

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Structure and dynamics of higher vibronic levels in the methyl radical Rydberg 3s state

Cited by 26 publications

References 2 publications

Multireference CI Study of Excitation Energies and Potential Energy Surfaces of CH₃F

Multireference CI Study of Excitation Energies and Potential Energy Surfaces of CH₃F

Femtosecond predissociation dynamics of the methyl radical from the 3p_z Rydberg state

Imaging the photodissociation dynamics of the methyl radical from the 3s and 3p_z Rydberg states

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Structure and dynamics of higher vibronic levels in the methyl radical Rydberg 3s state

Cited by 26 publications

References 2 publications

Multireference CI Study of Excitation Energies and Potential Energy Surfaces of CH3F

Multireference CI Study of Excitation Energies and Potential Energy Surfaces of CH3F

Femtosecond predissociation dynamics of the methyl radical from the 3pz Rydberg state

Imaging the photodissociation dynamics of the methyl radical from the 3s and 3pz Rydberg states

Contact Info

Product

Resources

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Multireference CI Study of Excitation Energies and Potential Energy Surfaces of CH₃F

Multireference CI Study of Excitation Energies and Potential Energy Surfaces of CH₃F

Femtosecond predissociation dynamics of the methyl radical from the 3p_z Rydberg state

Imaging the photodissociation dynamics of the methyl radical from the 3s and 3p_z Rydberg states