Precisely locate the Ka = 1, A1 level in the acceptor symmetric O–D stretch excited state

Determine accurately the energy position of the Ka = 1, A1 rotation–tunneling level in the acceptor symmetric O–D stretch excited state of (D2O)2, which is currently uncertain due to broad predissociation line widths.

Background

The Ka = 1 levels in the excited acceptor symmetric O–D stretch exhibit substantial broadening, complicating precise energy determination.

A precise level position is needed to quantify tunneling splittings and rotational constants in the excited state and to compare with theoretical models of vibrationally induced changes in tunneling dynamics.

References

The precise excited state Ka = 1, A1 level position is uncertain due to its broad observed width (~0.04 cm-1).

— Spectra of the D2O dimer in the O-D fundamental stretch region: the acceptor symmetric stretch fundamental and new combination bands (2402.14923 - Barclay et al., 22 Feb 2024) in Figure 5 caption (Section IV.A, Discussion of tunneling splittings)