On optical dispersion in transparent molecular systems

Abstract

The inelastic optical scattering process leading to the generation of the recently reported new molecular state (being stable at 100 K) of sodium nitroprusside is investigated. The process is a strong function of the phase coherence (Glauber state) of the incident light.-With laser light of 20–200 mW/cm² the yield of new molecular states rapidly reaches saturation, about 50% of all molecules of an extended target. The generation process is a linear function of the product: light intensity × illumination time. The coherent yield function follows a very simple law which, however, is different from predictions of linear or non-linear optics. It is a strong function of the laser frequency (range at least (4900±400) Å) and of the optical polarization relative to the oriented molecules. — The yield obtained with chaotic light is one order of magnitude smaller and weaker dependent upon frequency and polarization. The chaotic yield function depends exponentially upon the light intensity and illumination time in a way as to be expected from linear optics. — The coherently generated new molecular states can be depopulated by chaotic light (or by thermal agitation at elevated temperatures) and coherently regenerated arbitrarily often. There is further evidence that the recently reported properties of the new state are predominantly determined by the internal molecular structure. The lifetimeτ≫10⁷ s at 100 K.