Perturbation facilitated two-color four-wave-mixing spectroscopy of C3.

摘要: Perturbation-facilitated two-color resonant four-wave-mixing spectroscopy is realized to access the (dark) triplet manifold of C3 molecule from singlet X1Σg+ ground state. The inherent nonlinear signal dependence and coherence technique result in a favorable detection excited states interest. observation newly found 3Δu electronic state achieved by two-step excitation via “gate-way” levels (i.e., singlet-triplet mixed levels). Additionally, fixing probe laser on transition exhibiting mainly triplet-triplet character scanning pump laser, we demonstrate an effective spin-filtering four-wave mixing measurement where only transitions perturber Σu−3 appear exclusively otherwise congested spectral range Comet band. Ab initio calculations complement our analysis with assignment observed resonances.