From the above analysis, we, therefore, conclude that for the valence excitations of these azobenzene compounds in the gas phase, NSCD essentially probes ⟨k| ĥpso |m⟩ E k -Em , i.e., the transition densities between excited states. Where the result is dominated by one or two states that are energetically close to the probed states, we can understand some of the sign patterns, e.g., when states interchange.