Elimination mechanisms of Br2+ and Br+ in photodissociation of 1,1- and 1,2-dibromoethylenes using velocity imaging technique

Lee, Hua; Lee, Wei‐Bin; Chao, Meng-Hsuan; Zhang, Bing; Lin, King‐Chuen

doi:10.1063/1.3584178

Cited by 11 publications

(2 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Reliable band assignments combined with accurate modeling of vibrational couplings and high-level ab initio calculations provide the detailed basic data that, − coupled to the different experimental methods developed for reducing the spectral congestion (for example the use of cooling cells, − and supersonic jet expansion − ) and with the aid by sophisticated data-processing techniques, − are necessary to guide and support the rovibrational analysis. In addition to the spectroscopic interest due to the environmental issues related to the presence of haloethenes in the atmosphere, the potential threat to the stratospheric ozone layer related to their photodissociation and corresponding release of halogen atoms motivated many studies on the elimination mechanisms and distributions of kinetic energy, − the kinetics of their reactions with O( 3 P), and their photochemistry. , …”

Section: Introductionmentioning

confidence: 99%

Study of the Vibrational Spectra and Absorption Cross Sections of 1-Chloro-1-fluoroethene by a Joint Experimental and Ab Initio Approach

et al. 2016

View full text Add to dashboard Cite

The gas-phase infrared spectra of 1-chloro-1-fluoroethene (geminal chloro-fluoroethene, ClFC=CH, 1,1-CHClF) were recorded at medium resolution in the range 400 - 6400 cm and the vibrational analysis led to revise the previous assignments for the ν (A'' symmetry), ν (A' symmetry) and ν (A' symmetry) bands. Besides the fundamentals, all the most relevant spectral features were interpreted in terms of overtone and combination bands, thus obtaining an accurate description of the vibrational structure of ClFC=CH2. Accurate measurements of absorption cross section spectra were carried out and integrated band intensity data were determined. High-level ab initio calculations of harmonic and anharmonic force fields thoroughly supported and guided the analysis and the disentangling of the several strongly coupled polyads involving many vibrational levels. Diagonalization of the effective Hamiltonian with the off-diagonal elements involving several Fermi and Darling-Dennison resonance coefficients computed by the theoretical cubic and quartic force constants provided the predicted energy levels in good agreement with the vibrational assignments. The calculated infrared intensities, obtained by taking into account anharmonic corrections, were compared to the accurate experimental absorption cross section data here determined.

show abstract

Section: Introductionmentioning

confidence: 99%

Study of the Vibrational Spectra and Absorption Cross Sections of 1-Chloro-1-fluoroethene by a Joint Experimental and Ab Initio Approach

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Due to the importance in the field of atmospheric physics and environment chemistry, plenty of studies have been focused on the carbon halogen dissociation by single-photon excitation using ultraviolet laser field [8,9,10,11]. H.K.…”

Section: Introductionmentioning

confidence: 99%

Dissociative Ionization and Coulomb Explosion of Molecular Bromocyclopropane in an Intense Femtosecond Laser Field

et al. 2018

View full text Add to dashboard Cite

The dissociative ionization and Coulomb explosion of molecular bromocyclopropane (BCP) has been experimentally investigated by time-of-flight mass spectrum and dc-slice imaging technology. The sliced 2D images, kinetic energy releases and angular distributions of the fragment ions are obtained under the intense femtosecond laser fields (8.0 × 1013–2.0 × 1014 W/cm2). The results indicated that the low kinetic energy release (KER) components come from dissociative ionization of BCP+, while the high KER components come from Coulomb explosion of BCP2+. The chemical reaction path of BCP+ has been calculated by ab initio calculation, furthermore, the C-Br bond cleavage involved Coulomb explosion channels have been revealed, and the corresponding dehydrogenation mechanism has been confirmed.

show abstract

Beyond the rule of transition state: Identification of roaming routes in some cases of carbonyl compounds

Lin

Tso

Kasai

2021

J Chinese Chemical Soc

View full text Add to dashboard Cite

This account focuses on photodissociation of carbonyl compounds to verify a so‐called roaming route, alternative to those passing through a transition state (TS) invoked in the realm of the kinetics of elementary chemical processes. Such a roaming route bypasses the minimum energy path but produces the same molecular products. The photodissociation of the carbonyl compounds of study includes methyl formate (HCOOCH3), formic acid (HCOOH), and aliphatic aldehydes (RCOH, RH, CH3, and large alkyl group). Methyl formate and formic acid were promoted to the excited state, followed by internal conversion via a conical intersection. Then, the energetic precursor dissociated to fragments, which proceeded along either TS or roaming path. As the excitation energy increases, the roaming fraction in methyl formate is significantly interfered with by an open channel of triple fragmentation (H + CO + CH3O), whereas such a channel may not occur in formic acid even at an excitation wavelength of 193 nm. As a distinct roaming type, aliphatic aldehydes are found to possess the structure of the roaming saddle point comprising two moieties weakly bound at a distance. The energy difference between the TS barrier and the roaming saddle point is indicative of the extent for the roaming contribution. The roaming route becomes increasingly dominant when the aliphatic aldehyde is larger. Experimentally, ion imaging was employed to visualize the rotational‐level dependence of the roaming route, while time‐resolved Fourier‐transform infrared emission spectroscopy was applied to determine the vibrational‐state dependence. The roaming signature was verified theoretically by quasi‐classical trajectory calculations. As an alternative, a multi‐center impulsive model was developed to simulate the roaming scalar and vector properties without involving the global energy surface.

show abstract

Elimination mechanisms of Br2+ and Br+ in photodissociation of 1,1- and 1,2-dibromoethylenes using velocity imaging technique

Cited by 11 publications

References 38 publications

Study of the Vibrational Spectra and Absorption Cross Sections of 1-Chloro-1-fluoroethene by a Joint Experimental and Ab Initio Approach

Study of the Vibrational Spectra and Absorption Cross Sections of 1-Chloro-1-fluoroethene by a Joint Experimental and Ab Initio Approach

Dissociative Ionization and Coulomb Explosion of Molecular Bromocyclopropane in an Intense Femtosecond Laser Field

Beyond the rule of transition state: Identification of roaming routes in some cases of carbonyl compounds

Contact Info

Product

Resources

About