Excitações rotacionais de moleculas poliatomicas pelo impacto de eletrons de baixa energia

AUTOR(ES)
DATA DE PUBLICAÇÃO

1997

RESUMO

In the present work, the Schwinger Multichannel Method with Pseudopotentials (SMCPP) was applied, along with the Adiabatic Nuclei Rotation (ANR) approximation, to study rotational excitations of XH4 (X: C, Si, Ge, Sn, Pb), XH3 (X: N, P, As, Sb), CX4 (X: F, Cl), SiX4 (X: Cl, Br, I), CClF3 and CCl3F by electron impact (7.5 to 30 eV). For CH4, SiH4 and NH3, our rotationally resolved cross sections showed good agreement with previously reported results. (Methane is the only polyatomic system with available rotationally resolved experimental data. The agreement was encouraging.) For the other molecules, this is the first effort of rotational resolution of the collisions. Comparison between rotationally summed and unresolved (elastic) cross sections showed the expected good agreement. It was found that three aspects play relevant roles in determining the magnitude of rotationally inelastic cross sections: ( i ) the sphericity of the e--target interaction potential (in the case of Td molecules); ( ii ) permanent dipole moments (in the case of C3v molecules); ( iii ) the presence of heavy atoms (in general). The magnitude of rotationally inelastic cross sections is relevant for technological purposes since it gives an idea of how fast the systems would get rotationally hot in discharge environments. For targets presenting permanent dipole moments, the first Born approximation (FBA) was used along with the SMCPP to improve the quality of the cross sections near the forward scattering direction

ASSUNTO(S)

rotação molecular eletrons - espalhamento

ACESSO AO ARTIGO

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