Banca de DEFESA: BELIATO SANTANA CAMPOS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : BELIATO SANTANA CAMPOS
DATA : 28/11/2019
HORA: 09:00
LOCAL: Instituto de Física da Universidade Federal da Bahia
TÍTULO:

STUDY BY INFRARED TECHNIQUE OF CONDENSED CO2 RADIOLYSIS AT DIFFERENT TEMPERATURES, INDUCED BY ENERGY IONS OF H +, HE + AND N +

PALAVRAS-CHAVES:

Astrophysical Ice - Study of Radiolysis

PÁGINAS: 142
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Física
RESUMO:

The research developed in this doctoral work describes the study of CO2 molecule radiolysis by energetic ions, whose results present contributions to works performed with astrophysical ice. For this, experiments were carried out, which can be observed in light of simulations of interactions that occur in astrophysical environments, once the CO2 molecule was irradiated in condensed phase (at different temperatures, between 10 K and 75 K), with different projectiles (H +, He + and N + ions), whose energies ranged from 1.7 to 2.0 MeV. The in situ analysis was made possible by the infrared absorption technique using a Fourier transformed spectrometer. From the analysis of infrared absorption curves, shock sections were assigned from a radiolysis process (destruction - σd and creation - σc). For 2 MeV at 10 K, σd = 5.0 x 10-14 cm2, while for H + with the same energy at 75 K, σd = 8.7 x 10-14 cm2. The other ions (He + and N +) followed the same trend: the higher the temperature, the greater the apparent destruction section of the molecule, obeying an empirical function of the kind. It was also observed that the destruction of CO2 causes the formation of new species in the ice condensate CO2, being CO, CO3 and O3, having 75 K as the most efficient temperature for radiolysis processes. This trend was also repeated for the heavier ions (He + and N +). From the shock section values in relation to the Stopping Power (Se) it was obtained its variation with the temperature, according to the power law, with parameter values between 0.73 and 1.9. In addition, a study of the band displacement of the CO2 molecule and its fragments was performed. Another result was the determination of Sputtering dependence (Y) as a function of temperature (T) and energy transferred by the projectile, Stopping Power (Se), Y = Yo + A. Se (0.1 + B.T). exp (T / C). Another issue analyzed was the medium intensity flux. Through this flux, it is possible to estimate the speed of processes induced by these energetic beams in different regions of the MI.

MEMBROS DA BANCA:
Interno - 664720 - ANTONIO FERREIRA DA SILVA
Externo à Instituição - CARLOS EDUARDO FELLOWS - UFF
Externo ao Programa - 3036602 - CLAUDIO HANASHIRO BARBOSA SILVA
Externo à Instituição - DIANA PAULA DE PINHO ANDRADE
Presidente - 1878138 - LUIZ ANTONIO VIEIRA MENDES