Study of the Ionic Fragmentation of Dimethyl Diselenide, CH3SeSeCH3, with Synchrotron Radiation around the Se 3p Region.

MARIANA GERONÉS; LUCAS S. RODRÍGUEZ PIRANI; MAURICIO F. ERBEN; ANGÉLICA MORENO BETANCOURT; ROSANA M. ROMANO; REINALDO L. CAVASSO FILHO; CARLOS O. DELLA VÉDOVA

Campinas

Otro; 22ª RAU, Reunião Anual de Usuários do LNLS/CNPEM; 2012

LNLS/CNPEM

In this work we present a study of the dissociative photoionization of the volatile selenium compound CH3SeSeCH3 by using multicoincidence time-of-flight mass spectrometry and synchrotron radiation in the Se 3p edge. Gaseous selenium species detected in the atmosphere include dimethyl selenide, dimethyl selenone, methaneselenol and the title compound, dimethyl diselenide. Various plants can accumulate Se up to the thousands of ppm. These are called accumulators and they have potential to remediate areas contaminated with this metalloid (phytoremediating). SeSeCH3 by using multicoincidence time-of-flight mass spectrometry and synchrotron radiation in the Se 3p edge. Gaseous selenium species detected in the atmosphere include dimethyl selenide, dimethyl selenone, methaneselenol and the title compound, dimethyl diselenide. Various plants can accumulate Se up to the thousands of ppm. These are called accumulators and they have potential to remediate areas contaminated with this metalloid (phytoremediating) being an attractive solution for cleaning such sites. Certain plants can also convert the Se into volatile species, such as dimethyl selenide or dimethyl diselenide, mainly harmless to the environment, by a process called phytovolatilization. Below the Se 3p threshold, located at approximately 179.0 eV, the TIY spectrum exhibits two signals at 164.3 eV and 170.2 eV which should correspond to transitions involving the spin-orbit splitting of the 3p term of  selenium into 3p1/2 and 3p3/2 being an attractive solution for cleaning such sites. Certain plants can also convert the Se into volatile species, such as dimethyl selenide or dimethyl diselenide, mainly harmless to the environment, by a process called phytovolatilization. The analysis of the PEPICO spectra of CH3SeSeCH3 over the whole range of photon energies analyzed here reveals a preferential production of H+ ions, while signals corresponding to ionic fragments H2 +, CHx + (x= 2, 1 and 0) , Se+ and HCSe+ appear as less intense bands. In addition, peaks corresponding to the H3 + and Se2 + ions have been observed having very weak relative intensity. It should be noted that only a singly charged molecular ion can produce Se2 + from ionized CH3SeSeCH3 by the loss of two CH3 groups. The molecular ion, CH3SeSeCH3 +, can not be observed in any PEPICO spectra measured in these photon energies. Naturally occurring isotopomer fragments, due to the presence of Se isotopes, have been observed due to the suitable mass resolution attained in the experiments.SeSeCH3 by using multicoincidence time-of-flight mass spectrometry and synchrotron radiation in the Se 3p edge. Gaseous selenium species detected in the atmosphere include dimethyl selenide, dimethyl selenone, methaneselenol and the title compound, dimethyl diselenide. Various plants can accumulate Se up to the thousands of ppm. These are called accumulators and they have potential to remediate areas contaminated with this metalloid (phytoremediating) being an attractive solution for cleaning such sites. Certain plants can also convert the Se into volatile species, such as dimethyl selenide or dimethyl diselenide, mainly harmless to the environment, by a process called phytovolatilization. Below the Se 3p threshold, located at approximately 179.0 eV, the TIY spectrum exhibits two signals at 164.3 eV and 170.2 eV which should correspond to transitions involving the spin-orbit splitting of the 3p term of  selenium into 3p1/2 and 3p3/2 being an attractive solution for cleaning such sites. Certain plants can also convert the Se into volatile species, such as dimethyl selenide or dimethyl diselenide, mainly harmless to the environment, by a process called phytovolatilization. The analysis of the PEPICO spectra of CH3SeSeCH3 over the whole range of photon energies analyzed here reveals a preferential production of H+ ions, while signals corresponding to ionic fragments H2 +, CHx + (x= 2, 1 and 0) , Se+ and HCSe+ appear as less intense bands. In addition, peaks corresponding to the H3 + and Se2 + ions have been observed having very weak relative intensity. It should be noted that only a singly charged molecular ion can produce Se2 + from ionized CH3SeSeCH3 by the loss of two CH3 groups. The molecular ion, CH3SeSeCH3 +, can not be observed in any PEPICO spectra measured in these photon energies. Naturally occurring isotopomer fragments, due to the presence of Se isotopes, have been observed due to the suitable mass resolution attained in the experiments.