Photofragmentation of CF3I+ produced by resonant multiphoton ionization

Abstract

Photofragmentations, state interactions, and energetics of Rydberg and ion-pair states: Resonance enhanced multiphoton ionization via E and V (B) states of HCl and HBr J. Chem. Phys. 138, 044308 (2013); 10.1063/1.4776260 Two-dimensional resonance enhanced multiphoton ionization of H i Cl; i = 35, 37: State interactions, photofragmentations and energetics of high energy Rydberg states J. Chem. Phys. 134, 164302 (2011); 10.1063/1.3580876 Polarizationresolved (2+1) resonanceenhanced multiphoton ionization spectroscopy of CF3I (6s) Rydberg states J. Chem. Phys. 98, 4355 (1993); 10.1063/1.464997[3+2] resonance enhanced multiphoton ionization of I and Br formed from the infrared multiphoton decomposition of CF3I and CF3BrTime-of-flight mass spectrometry has been used to examine the spatial aniso.tropy and. . translational energy of 1+ and CFt fragments resulting from resonant multtphoton excttatIon of CF 31 in the 300-306 nm range. These ion species are shown to be largely the photofragments from the single-photon direct dissociation of CF 3 1+ generated via a new resonant (2 + 1) multi photon ionization (MPI) transition. ghotoelectron spectroscopy shows that most of the parent CF 3 1+ is produced in its ground X 2E3/2 state by the resonant MPI process .. All the observed 1+ is formed via this parent ion photodissociation, while the observed CFt IS formed via statistical decomposition of the parent as well as parent ion photodissociation. The present results are discussed in the context of the current understanding of alkyl halide photodynamics.

Neutral photodissociation of superexcited states of molecular iodine

“…Of course, this spectroscopy requires tunable laser light, though not necessarily in the vacuum ultraviolet. For example, in a molecule such as CF 3 I, recently studied by Aguirre and Pratt 38,39 and by Waits et al, 40 the ionization potential of CF 3 I is 10.3716 eV, and the dissociation energies for CF 3 I + to CF 3 + +I͑ 2 P 3/2 ͒ or CF 3 +I + ͑ 3 P 2 ͒ are 1.012 and 2.41 eV, respectively. Thus, dissociative ionization to CF 3 + is possible above 11.384 eV ͑or three photons at wavelengths below 326 nm͒, whereas dissociative ionization to I + is possible above 12.782 eV ͑or three photons at wavelengths below 291 nm͒.…”

Velocity map imaging of the photodissociation of CF3I+ in the Ã←X̃ band

“…The electronic structure of CF 3 I ϩ has been slowly unveiled by photodissociation [1][2][3][4] and photoionization 5,6 studies. The He͑I͒ photoelectron spectrum ͑PES͒ of CF 3 I recorded by Cvitas et al 5 revealed a series of low-lying excited states.…”

“…Using this approach, Taatjes et al 8 observed the rotational-and vibrational-state dependence in the photodissociation of CF 3 I ϩ via the C state of the neutral molecule. Similarly, Waits et al 1 used translational spectroscopy to characterize the time-of-flight profiles of CF 3 ϩ and I ϩ ions formed following MPI via a series of vibrational levels of the ͓ 2 E 3/2 ͔6 p Rydberg state. Waits et al suggested that some CF 3 ϩ and I ϩ fragments are produced by the dissociation of CF 3 I ϩ ions by absorption of an additional photon, while a second population of CF 3 ϩ is produced by the unimolecular decomposition of vibrationally hot CF 3 I ϩ in the electronic ground state that are directly produced in the photoionization of the ͓ 2 E 3/2 ͔6 p state.…”

Femtosecond pump–probe mass spectra on the dissociative photoionization of CF3I

“…CF 2 I þ can be observed at an excitation energy of 13.4 eV [20,24] or 14.58 eV [25], but in our experiments, we have never observed this fragment ion. No cluster formation appeared also.…”

“…When the two-photon energy is varied between 62 500 and 62 918 cm À1 , ionization through the e D D state provides very weak signals [19]. For higher energy, using (2 þ 1) REMPI, Waits et al [20] observed a Rydberg state at around 66 000 cm À1 which was ascribed to a 6p Rydberg state. Macleod et al [21] studied the 6p Rydberg states by using high-resolution ZEKE-PFI photoelectron spectrum, which allowed the assignment of the majority of the vibronic structure of the 6p Rydberg states.…”