Raman resonance de-enhancement in the excitation profile of CS2

摘要: The total differential Raman cross section of the symmetric vibrational mode CS2 (652 cm−1) in liquid phase has been measured as a function excitation wavelength from visible to ultraviolet. resulting profile shows strong preresonance enhancement when is less than 300 nm. at 240 nm about three orders-of-magnitude larger ν4 dependence for scattering. observed preresonant effect appears be dominated by 1B2(1Σu+)←1Σg+ transition. A minimum occurs that associated with peak near-UV absorption band (∼320 nm). dip ascribable quantum interference between 1B2(1Σu+) and two Renner–Teller components, 1B2 1A2(1Δu). transition ground state lower electronic electronically forbidden, but it becomes vibronically allowed due interaction. This may first ...