The role of orbiting resonances in the vibrational relaxation of I2(B,v'=21) by collisions with He at very low energies: a theoretical and experimental study

Abstract

In the last years there has been a controversy about whether the origin of the unexpectedly large cross sections found experimentally for the I2(B,v’) vibrational relaxation induced by collisions with He at very low collision energies was related to the presence of orbiting resonances [1-3]. More recently, measured cross sections for I2(B,v’=21) vibrational relaxation upon low temperature collisions with He exhibited for the first time clear peaks at given collision energies (Fig. 1) that were attributed to orbiting resonances of the I2(B,v’=21)-He vdW complex formed in the low energy collisions [4,5]. Further recent wave packet simulations (assuming zero total angular momentum) confirmed that the peaks in the experimental cross sections are the signature of orbiting resonances of the I2(B,v’=21)-He complex [6].