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

Abstract

The stepwise two-step two-color and three-step three-color laser excitation schemes are used for selective population of rovibronic levels of the first-tier ion-pair E0(g)(+) and D0(u)(+) states of molecular iodine and studies of non-adiabatic transitions to the D and E states induced by collisions with M = I(2)(X) and H(2)O. Collection and analysis of the luminescence after excitation of the v(E) = 8, 13 and v(D) = 13, 18 vibronic levels of the E and D states in the pure iodine vapor and the gas-phase mixtures with H(2)O provide rate constants for the non-adiabatic transitions to the D and E state induced by collisions with these molecules. Vibrational distributions for the [formula: see text] collision-induced non-adiabatic transitions (CINATs) are obtained. Rather strong λ(lum)(max) ≈ 3400 Å luminescence band is observed in the I(2) + H(2)O mixtures, whereas its intensity is ~100 times less in pure iodine vapor. Radiative lifetimes and quenching rate constants of the I(2)(E,v(E) = 8, 13 and D,v(D) = 13, 18) vibronic state are also determined. Rate constants of the [formula: see text], v(E) = 8-54, CINATs are measured again and compared with those obtained earlier. New data confirm resonance characters of the CINATs found in our laboratory about 10 years ago. Possible reasons of differences between rate constant values obtained in this and earlier works are discussed. It is shown, in particular, that differences in rate constants of non-resonant CINATs are due to admixture of water vapor in iodine.

Experimental and Theoretical Studies of the HeICl Van der Waals Complexes in the Valence and Ion‐pair States

“…The procedures of measurements have been described in detail elsewhere (see Refs. [1,[28][29][30] and references). Integrated luminescence of the ICl(E) decay product was recorded using photomultiplier tube FEU100/Edmund Optics band pass filter, λ = 350-400 nm system.…”

“…The procedures of measurements and simulation of luminescence spectra have been described in detail elsewhere (see Ref. [28][29][30] and references). All the luminescence spectra measured are corrected by the spectral sensitivity function of the condenser/monochromator/detector system, which was determined at the same mutual positions of the light sources, condenser and entrance slit as those of the laser beams, condenser and slits (see details in Section 5.4.2 in Ref.…”

Hyperfine coupling of the iodine ${\boldsymbol{D}}{0}_{{\boldsymbol{u}}}^{+}$ andβ1gion-pair states

“…, 0, FCF 5 10 ; , The β state rovibronic levels can be populated in perpendicular transitions utilizing the standard two-step twocolor, hν 1 +hν 2 , OODR excitation scheme [27]…”

Effect of curve crossing induced dissociation on absorption and resonance Raman spectra: An analytically solvable model

“…The first report on such kind of transitions came into existence into 1932, when the pioneering works were published by Landau [17], Zener [18] and Stueckelberg [19] and by Rosen and Zener [20]. Since1932, there are numerous research papers have been published in this area using analytical as well as computational approach [21][22][23][24][25][26][27][28][29][30][31][32][33]. In our earlier publications we have reported analytical solution in those cases where two or more arbitrary potentials are coupled by Dirac Delta interactions [34,37,35,38,36,39].…”