Reaction dynamics of Y + O2→ YO(X,A′,A)+ O(3PJ) studied by the crossed-beam technique

Abstract

The dynamics of the reaction, Y + O2--> YO + O was studied by using the crossed-beam technique at several collision energies from 10.3 to 52.0 kJ mol(-1). The Y atomic beam was generated by laser vaporization and crossed with the O2 beam at a right angle. Among the energetically accessible electronic states of YO, the formation of the A2Pi and A'2Delta states was observed by their chemiluminescence at all collision energies. By analyzing the chemiluminescence spectra of YO(A2Pi(1/2,3/2)-X2Sigma+), vibrational state distributions and relative populations of spin-orbit states were determined for YO(A2Pi(1/2,3/2)). At low collision energies, the vibrational distributions agree quite well with those expected from the statistical energy partitioning, while a little deviation from the statistical expectation was observed at the highest energy, 52.0 kJ mol(-1). The populations of two spin-orbit states are in good agreement with the statistical expectations at all collision energies. The vacuum ultraviolet laser-induced fluorescence (VUV-LIF) technique was employed to determine the distributions of spin-orbit states of the product O(3P(J)) at two collision energies, 20.7 and 52.0 kJ mol(-1). The line shapes of the O atom transitions were analyzed to determine relative branching ratio of the ground state to the excited states of YO, i.e. YO(X2Sigma+)+ O(3P(J))vs. YO(A2Pi and A'2Delta)+ O(3P(J)). The results showed that the electronically excited YO was formed with comparable amount with the ground state which is statistically more favorable, and suggested the occurrence of two mechanisms taking place in the title reaction.

Reaction dynamics of Mo + O2 → MoO + O studied by a crossed-beam velocity map imaging technique

“…For several oxidation reactions, crossed-beam or beam-gas experiments have been carried out to clarify the reaction mechanism by measuring the product state distributions. [23][24][25][26][27] All reactions showed statistical energy disposal into vib-rotational and/or electronic degrees of freedom of the products, and the formations of intermediate complexes were suggested during the course of the reactions. The interaction with ionic potential surfaces was likely to explain the presence of the complexes.…”

Time-sliced ion-velocity imaging study of the reaction Y + O2→ YO + O

“…[1][2][3][4][5][6][7] Recently, we have studied the reaction of Y with O 2 , reaction (1), using the crossed-beam chemiluminescence and laser-induced fluorescence (LIF) techniques at several collision energies. 8 In this reaction, YO in the X 2 S + , A 0 2 D, and A 2 P states are accessible from the ground state reactants: Y(a 2 D 3/2,5/2 ) + O 2 (X 3 S À g ) -YO(X 2 S + , A 0 2 D, A 2 P) + O( 3 P J ), D r H 0 0 = À221 kJ mol À1 . 9 (1)…”

State-to-state chemiluminescence in reactions of Mn atoms with S2Cl2

“…In this context, transition metal atom reactions are of interest on a number of counts: the ionisation energies of the ground state atoms are too high for a long-range electron jump; the complex electronic structures of both the atoms and the potential product molecules mean that a large number of ionic and covalent potential surfaces, including different (and high) multiplicities, may be present and interact; and the partially filled d orbitals also allow for the possibility of 'non-harpoon' reactions, involving electron back-donation from the reagent molecule, [2][3][4] insertion into C-H 5 and N-O 4 bonds and formation of p-complexes. 6 While a number of investigations have concerned reaction dynamics of ground state atoms, including the detection of electronic chemiluminescence, [1][2][3][7][8][9] relatively few have focused on the low-lying excited states of the reagents. Apart from work in this laboratory on Mn*(a 6 D J , z 8 P J , a 4 D J ) reactions, [10][11][12] the only recent experimental studies of that type to have come to our attention are those on Ti*(a 5 F J ) + NO, O 2 , N 2 O, 8,9 V*(a 4 F J ) + NO, 13 Cu*( 2 D 5/2,3/2 ) + ClF 14 and Zr*(z 3 F 2 0 ) + CH 3 F, 15 although there were some other investigations in earlier years.…”

“…6 While a number of investigations have concerned reaction dynamics of ground state atoms, including the detection of electronic chemiluminescence, [1][2][3][7][8][9] relatively few have focused on the low-lying excited states of the reagents. Apart from work in this laboratory on Mn*(a 6 D J , z 8 P J , a 4 D J ) reactions, [10][11][12] the only recent experimental studies of that type to have come to our attention are those on Ti*(a 5 F J ) + NO, O 2 , N 2 O, 8,9 V*(a 4 F J ) + NO, 13 Cu*( 2 D 5/2,3/2 ) + ClF 14 and Zr*(z 3 F 2 0 ) + CH 3 F, 15 although there were some other investigations in earlier years. 1,7 For first row transition metal atoms at least, these excited states are the more interesting, as the ionisation energies are lower than for the ground states and the relatively unreactive .…”