Oscillator strengths and ionisation cross sections for the absorption of CF2Cl2 in the UV and VUV spectral regions. A MQDO study

Photodissociation Rate Constants for VUV Processes of CF3Cl and CF2Cl2 in the Upper Atmosphere. A MQDO Study

“…These have been obtained by making use of our recently calculated MQDO oscillator strengths and photoionization cross sections. 6,7 These values conform fairly well with experimental and theoretical values found in the literature. For the first of the two fragmentation processes experienced by CF 3 Cl, the one at λ ) 127.95 nm, the MQDO absorption oscillator strength values 7 were first transformed into spectral densities, df/dE, following a procedure originally developed by Fano and Cooper, 22 and then into the photoabsorption cross section through the expression, For the dissociative photoionization of both CF 3 Cl and CF 2 Cl 2 at λ ) 94.79 nm and λ ) 98.94 nm, respectively, we have employed the MQDO cross sections, 6,7 to find the corresponding absorption cross section through the photoionization efficiency values (η i ) given by Zhang et al 20,21 as follows,…”

“…Finally, the df/dE value for Process 3, the ionic dissociation of CF 2 Cl 2 at λ ) 98.94 nm (12.53 eV), has also been obtained from the corresponding MQDO photoionization cross section, 59.16 Mb. 6 The MQDO cross sections calculated at different free electron energies 6 agree rather well with the experimental values available in the literature, such as those reported by Novak et al 25 and by Cooper et al 26 . In both, previously published electronic-state branching ratios for CF 2 Cl 2 27 have been employed.…”

“…For the dissociative photoionization of both CF 3 Cl and CF 2 Cl 2 at λ = 94.79 nm and λ = 98.94 nm, respectively, we have employed the MQDO cross sections, , to find the corresponding absorption cross section through the photoionization efficiency values (η i ) given by Zhang et al , as follows, The above values are collected in Table for the three photolysis processes presently studied.…”

“…In this paper, we report our study of two of the simplest CFC's, CF 3 Cl and CF 2 Cl 2 , also known as Freon-13 and Freon-12, respectively. We have recently undertaken the theoretical calculation of some spectral properties of CF 2 Cl 2 6 and CF 3 Cl, 7 such as oscillator strengths for bound-bound transitions and photoionization cross sections for bound-continuum transitions. The Molecular Quantum Defect Orbital (MQDO) approach has been employed in the calculations.…”

Photodissociation of the δ(0,0) and δ(1,0) bands of nitric oxide in the stratosphere and the mesosphere: A molecular‐adapted quantum defect orbital calculation of photolysis rate constants

“…[10] The theoretical tool employed in the calculation of the photoabsorption cross sections has been the Molecular Orbital Quantum Defect (MQDO) approach, formulated within our group a decade ago [Martı ´n et al, 1996a]. This methodology has proved, in a number of works [Velasco et al, 2003a[Velasco et al, , 2003bMayor et al, 2004Mayor et al, , 2005aBustos et al, 2004], to yield quantitative intensities for electronic transitions involving one or two Rydberg states. Very recently, rotational resolution has been accurately introduced in the procedure [Mayor et al, 2005b].…”