High-resolution ro-vibrational and rotational spectroscopy of HC₃O⁺

Abstract

Applying a 4 K cryogenic ion trap machine, the linear ion HCCCO + has been investigated by high-resolution rovibrational and pure rotational spectroscopy. For this, a novel action spectroscopic technique,...

Leak-out spectroscopy as alternative method to rare-gas tagging for the Renner–Teller perturbed HCCH+ and DCCD+ ions

“…It is noteworthy that the fitted rotational temperature of the LOS spectrum (38 K) is significantly higher than the nominal trap temperature (16 K), while for the LIR spectrum this is not the case (both recorded and fitted temperatures are 90 K). This effect of the LOS technique has been previously observed by Asvany et al , 31 where they discuss that collisions of the ions with heaver species ( i.e. Ne) in an RF field leads to heating of the stored ions.…”

“…The LOS method is thus very universal, in particular compared to another tag-free method, laser-induced reactions (LIR 29,30 ), which has also been applied previously to the cis -bending of HCCH + , 23,24 but requires a suitable slightly endothermic reaction to be applicable. Leak-out spectroscopy has already been applied for the high-resolution ro-vibrational spectroscopy of C 3 H + , 28 ro-vibrational and double-resonance rotational spectroscopy of c-C 3 H 2 D + , H 2 CCCH + , and HCCCO + , 31 and to the RT inactive antisymmetric C–H stretch (ν 3 ) of HCCH + . 32 In these studies, the infrared excitation leading to collisional energy transfer was done in the 3 micron region, using narrow-bandwidth continuous-wave, or in some cases also ns-pulsed, radiation.…”

Gas-Phase Infrared Action Spectroscopy of CH2Cl+ and CH3ClH+: Likely Protagonists in Chlorine Astrochemistry

“…Now that the IR spectra of CH 2 Cl + and CH 3 ClH + have been detected at low spectral resolution, corresponding studies at high resolution are imperative, in particular, to permit radio astronomical searches. Following the very recent technical developments in action spectroscopy of molecular ions, high-resolution infrared spectroscopy of both species may be performed using leak-out spectroscopy [45], a new method that does not require any rare gas tagging and has already been shown, on several occasions, to yield spectra of superb signal-to-noise ratios [46][47][48][49]. The method may even be combined with millimeterwave radiation in a double-resonance fashion to derive accurate information about the pure rotational spectrum [46,47,50], a prerequisite for radio astronomy.…”

“…Following the very recent technical developments in action spectroscopy of molecular ions, high-resolution infrared spectroscopy of both species may be performed using leak-out spectroscopy [45], a new method that does not require any rare gas tagging and has already been shown, on several occasions, to yield spectra of superb signal-to-noise ratios [46][47][48][49]. The method may even be combined with millimeterwave radiation in a double-resonance fashion to derive accurate information about the pure rotational spectrum [46,47,50], a prerequisite for radio astronomy. Using the high-level CCSD(T) structural and force field calculations performed here, very good predictions of the ground state rotational and centrifugal distortion constants can be derived.…”

Discovery of H2CCCH+ in TMC-1

“…Subsequently, pure rotational lines were detected using a vibrational-rotational double resonance (DR) method. Such methods have been reviewed by Asvany & Schlemmer (2021), and the particular scheme involving LOS has only recently been demonstrated by Asvany et al (2023). An example measurement for H 2 CCCH + is shown in Fig.…”