On the spectroscopy of phosphaalkynes: Millimeter- and submillimeter wave study of C2H5CP

TL;DR

This study reports the first gas-phase spectroscopic characterization of ethyl phosphaethyne (C2H5CP) using millimeter- and submillimeter-wave spectroscopy, supported by high-level quantum-chemical calculations, highlighting its potential for radio astronomical detection.

Contribution

First spectroscopic analysis of ethyl phosphaethyne in the gas phase, combining experimental data with advanced quantum-chemical calculations.

Findings

Detected C2H5CP and 13C isotopologues up to 500 GHz.

Provided spectroscopic parameters for future astronomical searches.

Demonstrated the molecule's potential as a radio astronomical target.

Abstract

Ethyl phosphaethyne, C2H5CP, has been characterized spectroscopically in the gas phase for the first time, employing millimeter- and submillimeter-wave spectroscopy in the frequency regime from 75 to 760 GHz. Spectroscopic detection and analysis was guided by high-level quantum-chemical calculations of molecular structures and force fields performed at the coupled-cluster singles and doubles level extended by a perturbative correction for the contribution from triple excitations, CCSD(T), in combination with large basis sets. Besides the parent isotopologue, the singly substituted 13C species were observed in natural abundance up to frequencies as high as 500 GHz. Despite the comparably low astronomical abundance of phosphorus, phosphaalkynes, R--CP, such as C2H5CP are promising candidates for future radio astronomical detection.