be computed in a straightforward fashion from the Einstein $A$ coefficients [@jt624]. Such lifetimes have been shown to be important in both laboratory [@jt306; @jt340] and astronomical [@02GoMcGe.H3+; @05OkGeGo.H3+] environments. Indeed the radiative lifetime of a state is a key component in determining the critical density of species in that state and hence whether it exists in local thermodynamic equilibrium in a given environment. Our recent study of lifetimes based on use of ExoMol data suggested that methane should show particularly interesting lifetime effects [@jt624]. These computed lifetimes can be compared with experimental measurements, where available, providing a check on our calculated dipole moments. This is particularly useful for rovibronic spectra, where measurements of absolute transition intensities are unusual.

The second state-dependent property are Landé $g$-factors. These provide the behaviour of the states in the presence of a weak magnetic field as given by the Zeeman effect. Molecular spectra can provide important information on magnetic fields in stars, brown dwarfs and exoplanets [@13KuBexx.CrH; @15AfBexx]. For open shell diatomics, Landé $g$-factors are given by a fairly straightforward formula in terms of standard Hund’s case (a) quantum numbers [@02BeSoxx.diatom]. The vibronic wavefunctions computed by [Duo]{} [@jt609] contain the necessary information to compute 