Coincidence ion pair production (cipp) spectroscopy of diiodine

Abstract

Coincidence ion pair production (I+ + I−) (cipp) spectra of I2 were recorded in a double imaging coincidence experiment in the one-photon excitation region of 71 600–74 000 cm−1.

Real-time dynamics of vibronic wavepackets within Rydberg and ion-pair states of molecular iodine

“…Works by Bogomolov et À1 where Rydberg states of the iodine molecule I 2 ** are coupled with ion-pair (IP: I + I À ) states. [3][4][5] An essential aspect of the resulting dynamics is the efficiency of bound-to-free energy transfers when the Rydberg excitation is above the dissociation limit of the IP states. 3,4 The richness of this energy region first appeared in a seminal work by Mulliken.…”

“…Works by Bogomolov et al in 2014, von Vangerow et al in 2016 and Matthiasson et al in 2022 focused on an energy region between 71 500 and 74 500 cm −1 where Rydberg states of the iodine molecule I 2 ** are coupled with ion-pair (IP: I + I − ) states. 3–5 An essential aspect of the resulting dynamics is the efficiency of bound-to-free energy transfers when the Rydberg excitation is above the dissociation limit of the IP states. 3,4…”

“…8 I 2 ** Rydberg states are grouped in n s, n p, n d… series converging to I 2 + cation states, and in particular. 3,5,9 The I 2 + cation and I 2 IP states have very different geometries. Many coupling zones therefore exist between Rydberg and IP states, a driving force for the bound-to-free energy transfers mentioned above.…”

“…The 2022 work by Matthíasson et al documented one-photon excited Rydberg states of ungerade symmetry. 5 VUV synchrotron light was scanned over the 71 600–74 000 cm −1 energy range (by comparison, the ionisation energy of I 2 is 75 069 cm −1 ). 10 Excitation of Rydberg states I 2 ** was detected by recording I + and I − ion signals, taking advantage of the bound-to-free energy transfers.…”