Dissociation rate, fluorescence and Infrared radiative cooling rates of Naphthalene studied in electrostatic storage Miniring

Efficient radiative cooling of tetracene cations C18H12+: absolute recurrent fluorescence rates as a function of internal energy

“…Accounting for twophoton absorption was important to model the decay curves for t L > 3 ms for Mini-Ring and t L > 6 ms for DESIREE. Compared to simulations performed in the cases of naphthalene and anthracene in previous studies at Mini-Ring 20,21 , the extension of the simulations above t L = 6 ms allow us to follow the evolution of IEDs for lower internal energies. In these previous simulations, the knowledge of the dissociation rates was sufficient since, after laser absorption, the IED was shifted into an energy range where dissociation dominates over radiative cooling.…”

“…However, this is compensated by rather high electronic transition probabilities that lead to non-negligible RF rates at least in some internal energy ranges and in relation to typical dissociation and IR vibrational emission rates 23 . Indeed, it has been shown that the competition between dissociation and RF is strongly dependent on the internal energy and occurs mainly in the 5-9 eV range for small PAHs with less than twenty carbon atoms such as, e.g., naphthalene (C 10 H 8 ) and anthracene (C 14 H 10 ) where the corresponding lifetimes are in the 0.1-10 ms range 15,20,21 . Moreover, vibronic (Herzberg-Teller) coupling has recently been shown to enhance RF cooling compared to theoretical predictions where this coupling has been left out 24 .…”

“…[5][6][7] This topic has motivated substantial theoretical [8][9][10][11] and experimental efforts [12][13][14][15][16][17][18] in order to characterize the physics and the chemistry of this family of molecules (see Tielens 19 for a review). Using a compact room-temperature electrostatic ion-beam storage ring, the Mini-Ring, Martin et al 15,20,21 have demonstrated experimentally that the recurrent fluorescence (RF) process, which was initially proposed by Le ´ger et al 22 under the name of Poincare ´fluorescence, plays a major role for the survival of small PAH cations (naphthalene, anthracene, pyrene. .…”

“…23 Indeed, it has been shown that the competition between dissociation and RF is strongly dependent on the internal energy and occurs mainly in the 5-9 eV range for small PAHs with less than twenty carbon atoms such as, e.g., naphthalene (C 10 H 8 ) and anthracene (C 14 H 10 ) where the corresponding lifetimes are in the 0.1-10 ms range. 15,20,21 Moreover, vibronic (Herzberg-Teller) coupling has recently been shown to enhance RF cooling compared to theoretical predictions where this coupling has been left out. 24 The RF process should lead to significantly higher survival probabilities, which, for instance, may help explain the unexpectedly high abundances of cyanonaphtelene isomers observed in the Taurus molecular cloud -1 (TMC-1).…”

Experimental and theoretical study of photo-dissociation spectroscopy of pyrene dimer radical cations stored in a compact electrostatic ion storage ring

“…In our previous experimental works, we have been using our compact Mini-Ring, operated at room temperature to study the radiative cooling of PAH cations such as naphthalene, anthracene and pyrene. In all these cases, we have shown that a fast radiative cooling process referred to as recurrent fluorescence (RF), was responsible for the fast reduction of the internal energy of PAH cations produced in the plasma of an electron cyclotron resonance (ECR) ion source (28)(29)(30)(31). Recently, the RF photon emission has been directly detected for naphthalene cations using an ion beam trap (32).…”