Quantum states of hydrogen cations confined into spherical and nanotube-like potential wells: H2 +, H3 +(C 2h and C 2v ) and H3 +(D 3h )

In this work, the potential energy surfaces (PESs) of hydrogen-based cations H2+and H3+placed inside infinite potential wells, in the shape of an infinite cylinder and a sphere, are investigated. The calculations are performed using the diffusion Monte Carlo (DMC) technique. Different symmetries are studied, some of them for the first time. The PESs trends are rationalized. The Raman shift of A1′ mode of spherically confined H3+ is also calculated.