Neutral photodissociation of superexcited states of molecular iodine

O’Keeffe, Patrick; Stranges, D.; Houston, Paul L.

doi:10.1063/1.2777160

Cited by 5 publications

(7 citation statements)

References 35 publications

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“…They can be coupled by radiation in a one-photon ''parallel'' process with states 0 u and 2 u , respectively. States of this symmetry exist among the repulsive valence-shell states of I 2 correlating with the formation of a pair I( 2 P 3/2 ) + I( 2 P 1/2 ) in process (6). 25 This further supports the interpretation that these states can act as intermediates in a direct twophoton excitation, as we have argued above.…”

Section: Angular Anisotropy Of One-and Two-photon Excitation Of Isupporting

confidence: 80%

“…Our hypothesis about the participation of intermediate states of different symmetries is supported by the results obtained for channel C6 which corresponds to photodissociation after excitation of I 2 by one photon (6). Fig.…”

Section: Angular Anisotropy Of One-and Two-photon Excitation Of Isupporting

confidence: 75%

“…From a classical simulation we infer that this is not due to an averaging effect caused by the Fig. 11 Images displaying the difference in angular anisotropy of recoil directions for I( 2 P 1/2 ) fragment atoms with a TKER value corresponding to process (6) rotation of the excited molecule. To explain this value of the anisotropy parameter we suppose that direct two-photon excitation via multiple pathways involving intermediate states of different symmetry dominates over a stepwise process.…”

Section: Discussionmentioning

confidence: 96%

“…A very useful approach for the identification of dissociation channels is based on measuring the photofragments distribution as a function of kinetic energy release (KER), which has been applied to the study of I 2 photodissociation via high-lying states. 6,7 O'Keeffe and coauthors investigated photofragments appearing after twophoton excitation of I 2 at 193 nm into superexcited Rydberg states converging to the excited electronic state of the molecular ion I 2 + (B 2 S g + ). 6 Measurements of KER allowed these authors to conclude that these superexcited states dissociate via neutral channels giving rise to the pair I[R( 3 P J )] + I( 2 P 3/2 ), where I[R( 3 P J )] are Rydberg atoms converging to the I + ( 3 P J ) states of the ion with J = 2, 1, 0.…”

Section: Introductionmentioning

confidence: 99%

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Role of ion-pair states in the predissociation dynamics of Rydberg states of molecular iodine

Vangerow

Bogomolov

Dozmorov

et al. 2016

Phys. Chem. Chem. Phys.

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Using femtosecond pump-probe ion imaging spectroscopy, we establish the key role of I(+) + I(-) ion-pair (IP) states in the predissociation dynamics of molecular iodine I2 excited to Rydberg states. Two-photon excitation of Rydberg states lying above the lowest IP state dissociation threshold (1st tier) is found to be followed by direct parallel transitions into IP states of the 1st tier asymptotically correlating to a pair of I ions in their lowest states I(+)((3)P2) + I(-)((1)S0), of the 2nd tier correlating to I(+)((3)P0) + I(-)((1)S0), and of the 3rd tier correlating to I(+)((1)D2) + I(-)((1)S0). Predissociation via the 1st tier proceeds presumably with a delay of 1.6-1.7 ps which is close to the vibrational period in the 3rd tier state (3rd tier-mediated process). The 2nd tier IP state is concluded to be the main precursor for predissociation via lower lying Rydberg states proceeding with a characteristic time of 7-8 ps and giving rise to Rydberg atoms I(5s(2)5p(4)6s(1)). The channel generating I((2)P3/2) + I((2)P1/2) atoms with total kinetic energy corresponding to one-photon excitation is found to proceed via a pump - dump mechanism with dramatic change of angular anisotropy of this channel as compared with earlier nanosecond experiments.

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Section: Angular Anisotropy Of One-and Two-photon Excitation Of Isupporting

confidence: 80%

Section: Angular Anisotropy Of One-and Two-photon Excitation Of Isupporting

confidence: 75%

Section: Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Role of ion-pair states in the predissociation dynamics of Rydberg states of molecular iodine

Vangerow

Bogomolov

Dozmorov

et al. 2016

Phys. Chem. Chem. Phys.

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“…The resulting formation of high-n Rydberg fragments originates from the neutral dissociation of these superexcited states. 9 This method is complimentary to previous studies using fluorescence or photoelectron spectroscopy which favor the detection of low-n Rydberg fragments. In another report, the vibrational dynamics of the B 3 P + u state of molecular I 2 , as well as the ion pair states accessible from there by a one-photon transition, were observed using Femtosecond degenerate fourwave-mixing spectroscopy using an initial pump laser pulse.…”

Section: Halogensmentioning

confidence: 93%

Halogens and noble gases

Justik

2008

Annu. Rep. Prog. Chem., Sect. A: Inorg. Chem.

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This chapter reviews the literature reported during 2007 concerning the elemental halogens and noble gases as well as compounds containing these elements in their positive oxidation states. HighlightsThe 2007 literature for halogen chemistry is highlighted by the first accurate ab initio diatomic dissociation curve for F 2 , the preparation of a new metal iodate for nonlinear optics applications and the crystal structure of a novel hypervalent iodinecontaining polymer having 12-atom hexagonal rings. Noble gas chemistry advances include the first reproducible preparation of XeOF 2 and the first solid-state 131 Xe NMR study of a xenon-containing compound.

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Predissociation of high-lying Rydberg states of molecular iodine via ion-pair states

Bogomolov

Grüner

Кочубей

et al. 2014

The Journal of Chemical Physics

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Velocity map imaging of the photofragments arising from two-photon photoexcitation of molecular iodine in the energy range 73 500-74 500 cm(-1) covering the bands of high-lying gerade Rydberg states [(2)Π1/2]c6d;0g (+) and [(2)Π1/2]c6d;2g has been applied. The ion signal was dominated by the atomic fragment ion I(+). Up to 5 dissociation channels yielding I(+) ions with different kinetic energies were observed when the I2 molecule was excited within discrete peaks of Rydberg states and their satellites in this region. One of these channels gives rise to images of I(+) and I(-) ions with equal kinetic energy indicating predissociation of I2 via ion-pair states. The contribution of this channel was up to about 50% of the total I(+) signal. The four other channels correspond to predissociation via lower lying Rydberg states giving rise to excited iodine atoms providing I(+) ions by subsequent one-photon ionization by the same laser pulse. The ratio of these channels varied from peak to peak in the spectrum but their total ionic signal was always much higher than the signal of (2 + 1) resonance enhanced multi-photon ionization of I2, which was previously considered to be the origin of ionic signal in this spectral range. The first-tier E0g (+) and D(')2g ion-pair states are concluded to be responsible for predissociation of Rydberg states [(2)Π1/2]c6d;0g (+) and [(2)Π1/2]c6d;2g, respectively. Further predissociation of these ion-pair states via lower lying Rydberg states gives rise to excited I(5s(2)5p(4)6s(1)) atoms responsible for major part of ion signal. The isotropic angular distribution of the photofragment recoil directions observed for all channels indicates that the studied Rydberg states are long-lived compared with the rotational period of the I2 molecule.

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Neutral photodissociation of superexcited states of molecular iodine

Cited by 5 publications

References 35 publications

Role of ion-pair states in the predissociation dynamics of Rydberg states of molecular iodine

Role of ion-pair states in the predissociation dynamics of Rydberg states of molecular iodine

Halogens and noble gases

Predissociation of high-lying Rydberg states of molecular iodine via ion-pair states

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