Imaging the Mode-Selected Predissociation of OCS+[(v1v2v3)B̃2Σ+]

Chang, Cheng-Chun; Luo, Chu-Yung; Liu, Kopin

doi:10.1021/jp040717z

Cited by 27 publications

(19 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The longer delays were explored in an attempt to reduce the effect of space-charge, as demonstrated in studies of OCS + photolysis. 7 The "two-color" fragment ion yields were also low and required the use of long integration times (images were typically taken for g2 × 10 4 laser shots and in most cases images repeated three or four times to ensure consistency in the data). All cation photolyses reported here used a Sirah Cobra Stretch dye laser (pumped by a Spectra-Physics GCR 250 Nd:YAG laser), operating at a wavelength of 415.24 nm, with subsequent frequency doubling (BBO-A) crystal to yield λ 2 ) 207.6 nm radiation.…”

Section: Methodsmentioning

confidence: 99%

Imaging Studies of the Photodissociation of NH₃⁺ and ND₃⁺ Cations

2009

View full text Add to dashboard Cite

Velocity map ion imaging methods have been used to study the photofragmentation dynamics of state-selected NH3+ and ND3+ cations. The cations were prepared in selected nu2+ bending vibrational levels of the ground (x2A'') electronic state by two-photon resonant, three-photon ionization of NH3(ND3), via several different nu2' levels of the and ' Rydberg states. Subsequent excitation to the A2E state by absorption of a 207.6 nm photon resulted in N-H(D) bond fission and NH2+(ND2+) fragment ion formation. These fragments exhibit isotropic recoil velocity distributions, which peak at low kinetic energy but extend to the maximum allowed by energy conservation. Such findings accord with conclusions from earlier electron induced photoionization and photoelectron-photoion coincidence studies of NH3 at similar total energies (defined relative to the ground-state neutral) and, as previously, can be rationalized in terms of excitation to the Jahn-Teller distorted state, rapid radiationless transfer via one or more conical intersections linking the and state potential energy surfaces (PESs) and subsequent unimolecular decay on the latter PES. Weak NH2+ and NH+ fragment ion signals are also observed when exciting with the ionization laser only; imaging these fragment ions provides some insights into their likely formation mechanisms.

show abstract

Section: Methodsmentioning

confidence: 99%

Imaging Studies of the Photodissociation of NH₃⁺ and ND₃⁺ Cations

2009

View full text Add to dashboard Cite

show abstract

“…First, a turbo pump replaced the diffusion pump for the source chamber. Second, in view of the difficulty in time-slicing the photoelectron cloud, a simplified ion-optics assembly with significantly tighter focus and more restricted field-of-view than the original setup 17,18 was adapted for the conventional "crushed" velocity imaging. 1,2 The new setup consists of five thin electrodes (repeller, extractor, and three lenses) with the openings, in order of 10 mm, 10 mm, 20, 60, and 60 mm respectively.…”

Section: Methodsmentioning

confidence: 99%

Photoelectron Imaging of Atomic Iodine Following A-Band Photolysis of CH₃I

Pei

Chen

et al. 2007

J. Phys. Chem. A

Self Cite

View full text Add to dashboard Cite

Photoionization of the iodine atom following methyl iodide A-band photodissociation was studied over the wavelength range of 245.5-261.6 nm by photoelectron imaging technique. Final state-specific speed and angular distributions of the photoelectron were recorded. Two types of the photoelectron resulted from ionizing the I atom from the photodissociation of CH3I were identified: (a) (2+1) REMPI of the ground state I atom, and (b) two-photon excitation of spin-orbit excited I(2P1/2) to autoionizing resonances converging to the 3P1 state of I+. In addition, some weaker signals were attributed to one-photon ionization of I atoms produced in some higher excited states from multiphoton ionization of CH3I followed by dissociation. Analysis of relative branching ratios to different levels of I+ (in case a) revealed that the final ion level distributions are generally dominated by the preservation of the ion-core configuration of the intermediate resonant state. A qualitative interpretation of the electron angular distribution from an autoionization process is also given.

show abstract

“…In addition to the photodissociation of neutrals, the ion imaging measurements have been performed to observe the fragment ions produced by the photodissociation of molecular ions [17][18][19][20]. In these experiments, a mass-selected parent ion was initially generated by a resonance-enhanced multiphoton ionization (REMPI) and then dissociated into fragments by a photolysis laser.…”

Section: Introductionmentioning

confidence: 99%