Linear BeNCO and OBeNC: kinetically stable neutral Be-bearing free molecules

Abstract

This study investigates a [Be,N,C,O] system by employing density functional theory and coupled-cluster methods. The thermodynamic and kinetic stabilities of the [Be,N,C,O] isomers are predicted using the isomerization reaction potential energy profile constructed using stationary-point thermodynamic data. The lowest-lying linear BeNCO and OBeNC are kinetically stable and suitable for experimental observation. Electronic structural analysis suggests that the Be–N bonding and the Be–O bonding of BeNCO and OBeNC are dominated by ion interactions, with a minor covalent contribution. The equilibrium and vibrationally averaged permanent dipole moments of BeNCO and OBeNC are calculated, which can be used to characterize their intrinsic rotational transition intensities. Furthermore, the vibrational, rotational, and vibration–rotation interaction constants, along with the quartic and sextic centrifugal distortion constants and the equilibrium value of the quartic centrifugal distortion constant, are provided to further analyze the detailed vibrational, rotational, and vibration–rotation spectra of BeNCO and OBeNC in future experiments. These basic data may help in deeply understanding the structural characteristics of free BeNCO and OBeNC molecules.