Probing the vibrational spectroscopy of the deprotonated thymine radical by photodetachment and state-selective autodetachment photoelectron spectroscopy via dipole-bound states

Abstract

High-resolution state-selective autodetachment photoelectron spectroscopy via dipole-bound states and photodetachment spectroscopy of cryogenically cooled deprotonated thymine anions are reported.

Perspective: Electrospray photoelectron spectroscopy: From multiply-charged anions to ultracold anions

“…The simulation yielded a rotational temperature of T rot = 35 K, while the cryogenic trap was operated at 4.4 K measured off the trap surface using a silicon diode temperature sensor. More recent experiments on the deprotonated thymine anion gave rise to a similar rotational temperature, 157 whereas a slightly lower rotational temperature was observed for the smaller acetate anion (∼20-35 K), 158 which was the lowest rotational temperature achieved thus far in the cryogenic Paul trap. The discrepancy between the nominal trap temperature (4.4 K) and the achieved ion temperature is most likely due to the RF-heating.…”

“…The potentials of resonant PES via DBS have been illustrated in a number of recent studies. [157][158][159] The resonant PES led to the definitive determination of the 0-0 detachment transition in the acetate anion, allowing the EA of the acetyloxyl radical to be accurately and unambiguously measured. 158 Autodetachment spectroscopy and resonant PE images and spectra for the deprotonated thymine and the 2-hydroxyphenoxide anions have also been reported recently, 157,159 allowing the measurements of the vibrational frequencies of the corresponding neutral radicals and further demonstrating the potentials of resonant PES via DBS as a new technique for vibrational spectroscopy of novel radical species.…”

Tautomer‐Specific Resonant Photoelectron Imaging of Deprotonated Cytosine Anions

“…Thea ssignments of all the resonances are based on the calculated vibrational frequencies (Table S2) and the vibrational autodetachment in the resonant photoelectron spectra (Figures 3a-h), which yield tautomer-specific information. We have previously shown that vibrational frequencies in the DBS are the same as those in the neutral states, [33][34][35][42][43][44] that is,t he diffuse dipole-bound electron has little effect on the neutral cores.…”

“…[30][31][32] We have investigated autodetachment from the vibrational levels of DBS more recently for cryogenically cooled anions and obtained highly non-Franck-Condon resonant photoelectron spectra. [33][34][35] The corresponding radicals of the seven anions in Scheme 1a ll have dipole moments larger than 2.5 De xcept for the cEAOH8a radical (Table S1). Hence,e xcited DBSs are expected to be observed, allowing tautomer-specific resonant PEI to be performed.…”

“…Thep -wave angular distribution of the two-photon signals is consistent with ad etachment from an s-type dipole-bound orbital of tKAN3H8b À ,a sp reviously observed. [33][34][35] Above C EA, the peaks C 1to C 3correspond to vibrational levels of the DBS of cKAN3H8a À as ar esult of vibrational autodetachment. Thepeaks T 1to T 7represent the DBS vibrational levels of tKAN3H8b À .T he weaker peaks T 1and T 2below T EA are due to resonant two-photon detachment, while the strong peaks T 3t o T 7a re due to autodetachments from vibrational levels of the DBS of tKAN3H8b À .…”