REMPI Spectroscopy of SO Singlet States

Speth, R.; Braatz, C.; Tiemann, E.

doi:10.1006/jmsp.1998.7670

Cited by 23 publications

(5 citation statements)

References 15 publications

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“…The contributions of the neutral SO fragments, produced through two-pump-photon absorption, to the SO + TRPEPICO spectra will depend on the nature of the photoproduct distribution formed by our ultrashort pump pulses. Were similar two-pump-photon photoproduct distributions formed as those measured using nanosecond lasers by Effenhauser et al, 37 we may expect a photoproduct distribution predominantly made up of a 1:1 ratio of SO(X 3 − ) (T 0 = 0 eV) and SO(a 1 ) (T 0 = 0.797 eV 100 ) fragments formed in a wide range of rovibrational states. We highlight the increased SO + /SO + 2 ratio observed as higher pump beam intensities were implemented (see Fig.…”

Section: Interference From Two-pump-photon Excited State Relaxatiosupporting

confidence: 72%

Excited state dynamics in SO2. I. Bound state relaxation studied by time-resolved photoelectron-photoion coincidence spectroscopy

Wilkinson

Boguslavskiy

Mikosch

et al. 2014

The Journal of Chemical Physics

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The excited state dynamics of isolated sulfur dioxide molecules have been investigated using the time-resolved photoelectron spectroscopy and time-resolved photoelectron-photoion coincidence techniques. Excited state wavepackets were prepared in the spectroscopically complex, electronically mixed (${\tilde{\rm B}}$B̃)1B1/(Ã)1A2, Clements manifold following broadband excitation at a range of photon energies between 4.03 eV and 4.28 eV (308 nm and 290 nm, respectively). The resulting wavepacket dynamics were monitored using a multiphoton ionisation probe. The extensive literature associated with the Clements bands has been summarised and a detailed time domain description of the ultrafast relaxation pathways occurring from the optically bright (${\tilde{\rm B}}$B̃)1B1 diabatic state is presented. Signatures of the oscillatory motion on the (${\tilde{\rm B}}$B̃)1B1/(Ã)1A2 lower adiabatic surface responsible for the Clements band structure were observed. The recorded spectra also indicate that a component of the excited state wavepacket undergoes intersystem crossing from the Clements manifold to the underlying triplet states on a sub-picosecond time scale. Photoelectron signal growth time constants have been predominantly associated with intersystem crossing to the (${\tilde{\rm c}}$c̃)3B2 state and were measured to vary between 750 and 150 fs over the implemented pump photon energy range. Additionally, pump beam intensity studies were performed. These experiments highlighted parallel relaxation processes that occurred at the one- and two-pump-photon levels of excitation on similar time scales, obscuring the Clements band dynamics when high pump beam intensities were implemented. Hence, the Clements band dynamics may be difficult to disentangle from higher order processes when ultrashort laser pulses and less-differential probe techniques are implemented.

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Section: Interference From Two-pump-photon Excited State Relaxatiosupporting

confidence: 72%

Excited state dynamics in SO2. I. Bound state relaxation studied by time-resolved photoelectron-photoion coincidence spectroscopy

Wilkinson

Boguslavskiy

Mikosch

et al. 2014

The Journal of Chemical Physics

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“…3,4 Here, formation of two ground state 35 Cl fragments and the vibrational quantum o SO(X) ¼ 1150.7 cm À1 were considered. 42 For the molecular channel (3), the available energy is increased by the energy of the Cl-Cl bond in the Cl 2 molecule and therefore amounts to 24 550 AE 150 cm À1 . If Cl 2 is generated in the X 1 S g + ground state, the corresponding maximum SO kinetic energy is 14 560 AE 90 cm À1 , and the maximum speed is 2700 AE 20 m s À1 .…”

Section: So Speed and Spatial Distributionmentioning

confidence: 99%

Competitive channels in the photodissociation of thionyl chloride

Roth

Maul

Gericke

2002

Phys. Chem. Chem. Phys.

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The photodissociation dynamics of thionyl chloride are investigated by a one-dimensional resonance enhanced multi-photon/time-of-flight technique (REMPI/TOF) at a dissociation wavelength around 235 nm. Nascent sulfur monoxide molecules and chlorine atoms were detected state-specifically under collision-free conditions for parallel and perpendicular polarisation geometries. Dissociation and detection were performed using the same laser. Polarisation-dependent and state-specific TOF profiles were converted into kinetic energy distributions using a least squares fitting method taking into account velocity-dependent spatial fragment anisotropies. Kinetic energy distributions are narrow and structureless for SO and bimodal for both spin-orbit states of Cl. The bimodality reflects the competition between two-and three-body decay: SOCl 2 + hn ! SOCl + Cl and SOCl 2 + hn ! SO + 2 Cl. Chlorine atoms are preferentially released along the polarisation vector of the dissociation laser. The spatial distribution of Cl is characterised by an anisotropy parameter of 0.8 AE 0.2 for the two-body decay and 0.2 AE 0.2 for the three-body decay. SO molecules are isotropically released with low kinetic energy together with two ground state chlorine atoms. These products are most likely to be generated in a sequential three-body decay on a potential energy surface of A 0 symmetry. Another surface of A 00 symmetry instantaneously produces fast chlorine atoms in a two-body decay process to equal amounts in the ground and the excited spin-orbit states. The corresponding SOCl fragment carries about 50% of the available energy as internal energy.

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“…On the basis of the vibrational frequencies reported by Ornellas et al, the minimum vibrational energy corresponds to v = 20 and v = 14 in the SO( a 1 Δ) and the SO( b 1 Σ + ) fragments, respectively. In the two-photon dissociation of SO 2 between 248 and 291 nm, the SO fragment in the a 1 Δ and b 1 Σ + electronic states was observed to have high vibrational excitation .…”

Section: Resultsmentioning

confidence: 97%

“…In the two-photon dissociation of SO 2 between 248 and 291 nm, the SO fragment in the a 1 ∆ and b 1 Σ + electronic states was observed to have high vibrational excitation. 30 Effenhauser et al have studied the two-photon dissociation of SO 2 at 248 and 308 nm. 20 The three internal energy thresholds observed experimentally at 28500, 29100 and 30400 cm -1 were assigned respectively to SO(c 1 Σ -), SO(A′ 3 ∆), and SO(A′′ 3 Σ + ) states generated in coincidence with O( 3 P).…”

Section: O( 3 P) Imagementioning

confidence: 99%

Dissociation of Sulfur Dioxide by Ultraviolet Multiphoton Absorption between 224 and 232 nm

et al. 2005

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Multiphoton excitation and dissociation of SO(2) have been investigated in the wavelength range from 224 to 232 nm. Strong evidence is found for two-photon excitation to the H Rydberg state, followed by dissociation to SO + O and ionization of the SO product by absorption of a third photon. The two-photon excitation is resonantly enhanced via the C (1)B(2) intermediate state, and the two-photon yield spectrum thus bears a strong resemblance to the spectrum of this intermediate. Imaging of the O((3)P(2)), S((1)D(2)), and SO products suggests that, following dissociation of SO(2) from the H state, SO is produced in the A and B electronic states. S((1)D(2)) is produced both from two-photon dissociation of SO(2) to give S((1)D(2)) + O(2) and by single-photon dissociation of SO(+). In the former process, the O(2) is likely formed in all of its lowest three electronic states.

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REMPI Spectroscopy of SO Singlet States

Cited by 23 publications

References 15 publications

Excited state dynamics in SO2. I. Bound state relaxation studied by time-resolved photoelectron-photoion coincidence spectroscopy

Excited state dynamics in SO2. I. Bound state relaxation studied by time-resolved photoelectron-photoion coincidence spectroscopy

Competitive channels in the photodissociation of thionyl chloride

Dissociation of Sulfur Dioxide by Ultraviolet Multiphoton Absorption between 224 and 232 nm

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