Long-range collisional energy transfer between charge-transfer (ion-pair) states of I2, induced by H2O and I2(X)

Abstract

Long-range (resonant) energy transfer, between g/u charge-transfer states of molecular iodine [i.e., f0(g) (+)((3)P(0))-->F0(u)(+)((3)P(0)) and E0(g)(+)((3)P(2))-->D0(u) (+)((3)P(2))], induced by collisions with H(2)O and I(2)(X) via multipole coupling, has been observed. Large rate constants, up to 5 x 10(-9) molecules(-1) cm(3) s(-1), for collisional transfer between a range of vibrational levels of the f0(g)(+)((3)P(0)) and F0(u)(+)((3)P(0)) ion-pair states of I(2), by H(2)O, are reported. Some previously reported studies on E0(g)(+)((3)P(2))-->D0(u)(+)((3)P(2)) and f0(g)(+)((3)P(0))-->F0(u)(+)((3)P(0)) collisional transfer, induced by I(2)(X), have been repeated and revised rate data are presented; the range of initially excited vibrational states studied has also been extended. Much smaller rate constants for quenching by I(2)(X), compared to H(2)O, are found and it is proposed that H(2)O desorbed from the walls of the sample cell could have significantly affected much larger rate data previously reported in the literature. For both collision partners, a model is proposed in which long-range, near-resonant interactions can occur when there is close matching of the change in energy in the ion-pair states with the change in energy that accompanies the rotational transition undergone by the collision partner.

Non-adiabatic transitions from I2(${E} {\rm 0}_{g}^{+} $Eg+ and ${D}0_{u}^{+} $Du+) states induced by collisions with M = I2(${X}0_{g}^ + $Xg+) and H2O

“…values increase with v E due to increase of the I 2 (E -D) dipole moment 37 and, consequently, probability of the 38 There are differences between rate constant values of the well as Ref. 20 and earlier, especially for v E = 8 (Fig. 4).…”

“…Recently, it was shown that amplified spontaneous emission (ASE; Refs. [16][17][18][19] as well as water impurity 20 − −−− → D) CINAT rate constants. Very recently, the first experimental results for the ungerade D-state CINATs in collisions of molecular iodine with the rare gases Rg = He, Ar, Xe, as well as some preliminary data for the collisions with the I 2 (X) molecule 21 were reported.…”

Efficient long-range collisional energy transfer between the E g+(3P2) and D u+(3P2) ion-pair states of I2, induced by H2O, observed using high-resolution Fourier transform emission spectroscopy

“…With the exception of part of the broad band around 325 nm, all the emissions above 320 nm in the spectrum are due to E0 g collisional transfer is observed down to 275 nm which is the low-wavelength limit of the emission from the vibrational levels populated (v D = 10−13). Previously, 1 we showed that, under these conditions, the E0 g…”

“…As it was not possible to record any new spectra with this experimental arrangement, we were restricted to re-examining the original data in the light of our recent study. 1 Consequently, the ideal (v, J) combinations are not always available.…”

“…In a recent paper, 1 we reported long-range (resonant) energy transfer between g/u ion-pair states of molecular iodine, e.g., E0 g + ( 3 P 2 ) → D0 u + ( 3 P 2 ), induced by collisions with H 2 O via dipole coupling. The large rate constants deduced for collisional transfer between a range of vibrational levels of the two states, up to 5 × 10 −9 molecules −1 cm 3 s −1 , can be two orders of magnitude greater than that for transfer between the same two levels following collisions with I 2 (X).…”