Vibronic spectrum of 15N16O2 between 415 and 440nm

Volkers, E.; Bulthuis, J.; Stolte, S.; Jost, R.; Wehres, Nadine; Linnartz, H.

doi:10.1016/j.jms.2007.07.002

Cited by 5 publications

(6 citation statements)

References 31 publications

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“…3,4 The photoexcitation of NO 2 via the first excited state is known to be very complex due to a conical intersection coupling the ground and first excited states. The effect of this conical intersection has been extensively studied in the frequency 5,6 and more recently also the time domain. [7][8][9][10] Depending on the typical time scale of the dissociation dynamics, femtosecond pump-probe laser spectroscopy can be used.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond time-resolved photoelectron-photoion coincidence imaging of multiphoton multichannel photodynamics in NO2

Vredenborg¹,

Roeterdink²,

Janssen³

2008

The Journal of Chemical Physics

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The multiphoton multichannel photodynamics of NO 2 has been studied using femtosecond time-resolved coincidence imaging. A novel photoelectron-photoion coincidence imaging machine was developed at the laboratory in Amsterdam employing velocity map imaging and "slow" charged particle extraction using additional electron and ion optics. The NO 2 photodynamics was studied using a two color pump-probe scheme with femtosecond pulses at 400 and 266 nm. The multiphoton excitation produces both NO 2 + parent ions and NO + fragment ions. Here we mainly present the time dependent photoelectron images in coincidence with NO 2 + or NO + and the ͑NO + , e͒ photoelectron versus fragment ion kinetic energy correlations. The coincidence photoelectron spectra and the correlated energy distributions make it possible to assign the different dissociation pathways involved. Nonadiabatic dynamics between the ground state and the A 2 B 2 state after absorption of a 400 nm photon is reflected in the transient photoelectron spectrum of the NO 2 + parent ion. Furthermore, Rydberg states are believed to be used as "stepping" states responsible for the rather narrow and well-separated photoelectron spectra in the NO 2 + parent ion. Slow statistical and fast direct fragmentation of NO 2 + after prompt photoelectron ejection is observed leading to formation of NO + + O. Fragmentation from both the ground state and the electronically excited a 3 B 2 and b 3 A 2 states of NO 2 + is observed. At short pump probe delay times, the dominant multiphoton pathway for NO + formation is a 3 ϫ 400 nm+ 1 ϫ 266 nm excitation. At long delay times ͑Ͼ500 fs͒ two multiphoton pathways are observed. The dominant pathway is a 1 ϫ 400 nm+ 2 ϫ 266 nm photon excitation giving rise to very slow electrons and ions. A second pathway is a 3 ϫ 400 nm photon absorption to NO 2 Rydberg states followed by dissociation toward neutral electronically and vibrationally excited NO͑A 2 ⌺ , v =1͒ fragments, ionized by one 266 nm photon absorption. As is shown in the present study, even though the pump-probe transients are rather featureless the photoelectron-photoion coincidence images show a complex time varying dynamics in NO 2 . We present the potential of our novel coincidence imaging machine to unravel in unprecedented detail the various competing pathways in femtosecond time-resolved multichannel multiphoton dynamics of molecules.

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Section: Introductionmentioning

confidence: 99%

Femtosecond time-resolved photoelectron-photoion coincidence imaging of multiphoton multichannel photodynamics in NO2

Vredenborg¹,

Roeterdink²,

Janssen³

2008

The Journal of Chemical Physics

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“…Consequently, overtime it became a benchmark system for a variety of spectroscopic and dynamics studies concerning theoretical and experimental aspects of photodissociation, intramolecular vibrational redistribution, nonadiabatic couplings [1,2,3,4,5,6,7,8,9,10,11,12,13]. The numerous nonadiabatic interactions are reflected in a complex photodissociation dynamics.…”

Section: Introductionmentioning

confidence: 99%

Imaging fast relaxation dynamics of NO₂

et al. 2009

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Time-resolved spectroscopy combined with velocity map imaging technique have been used to investigate the multiphoton dynamics of NO 2 molecule. Two different pump-probe excitation schemes were used to explore different potential energy surfaces (PESs) located in the first dissociation region and in the Rydberg region around 9.2 eV. Integrated and energy resolved signals of NO + 2 , NO + and photoelectrons were recorded as a function of time. When exciting with 403 nm photons, the NO + signal exhibits an intriguing oscillatory behaviour with a period of 512 fs. The NO + and photoelectron kinetic energy distributions produced by this pump wavelength were cold, while those produced when employing 269 nm photons as pump were very rich, evidencing the presence of multiple excitation channels. A couple of sharp long lived photoion-photoelectron peaks represents the most salient feature of latter. They were assigned to an excitation by two 269 nm photons to a Rydberg state dissociating into NO(A 2 Σ + )+O( 3 P ). This NO + peak as well as another one located at 0 eV display very complex time dependencies including the signatures of two dissociation dynamics on timescales of 400 and 600 fs. The different pathways responsible of this temporal behaviour are discussed in view of shedding light onto the underlying multichannel multiphoton dynamics.

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“…This is expected to populate between 5 and 11 vibrational levels of the initially excited (1) 2 B 2 manifold. 39 This lack of selectivity in the initial excitation step mimics the initial excitation process in the time-resolved experiments reported in the introduction.…”

Section: Resultsmentioning

confidence: 67%

The photodissociation of NO2 by visible and ultraviolet light

Wilkinson

Garcia

Whitaker

et al. 2010

Phys. Chem. Chem. Phys.

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We present velocity map images of the NO, O((3)P(J)) and O((1)S(0)) photofragments from NO(2) excited in the range 7.6 to 9.0 eV. The molecule was initially pumped with a visible photon between 2.82-2.95 eV (440-420 nm), below the first dissociation threshold. A second ultraviolet laser with photon energies between 4.77 and 6.05 eV (260-205 nm) was used to pump high-lying excited states of neutral NO(2) and/or probe neutral photoproducts. Analysis of the kinetic energy release spectra revealed that the NO photofragments were predominantly formed in their ground electronic state with little kinetic energy. The O((3)P(J)) and O((1)S(0)) kinetic energy distributions were also dominated by kinetically 'cold' fragments. We discuss the possible excitation schemes and conclude that the unstable photoexcited states probed in the experiment were Rydberg states coupled to dissociative valence states. We compare our results with recent time-resolved studies using similar excitation and probe photon energies.

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Vibronic spectrum of 15N16O2 between 415 and 440nm

Cited by 5 publications

References 31 publications

Femtosecond time-resolved photoelectron-photoion coincidence imaging of multiphoton multichannel photodynamics in NO2

Femtosecond time-resolved photoelectron-photoion coincidence imaging of multiphoton multichannel photodynamics in NO2

Imaging fast relaxation dynamics of NO₂

The photodissociation of NO2 by visible and ultraviolet light

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Vibronic spectrum of 15N16O2 between 415 and 440nm

Cited by 5 publications

References 31 publications

Femtosecond time-resolved photoelectron-photoion coincidence imaging of multiphoton multichannel photodynamics in NO2

Femtosecond time-resolved photoelectron-photoion coincidence imaging of multiphoton multichannel photodynamics in NO2

Imaging fast relaxation dynamics of NO2

The photodissociation of NO2 by visible and ultraviolet light

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Imaging fast relaxation dynamics of NO₂