Femtosecond response in rare gas matrices doped with NO impurities: A stochastic approach

The femtosecond response of NO-doped rare gas matrices is studied within a stochastic Langevin theoretical framework. As is shown, a simple damped harmonic oscillator model can describe properly the absorption and emission line shapes associated with the NO ($A^2\Sigma^+ \longleftrightarrow X^2\Pi$) electronic transitions inside these media as well as the matrix first-solvation shell response in a process with two timescales, finding a fairly good agreement with available experimental data. This approach thus constitutes an alternative and complementary way to analyze the structural relaxation dynamics of systems in liquids and solids, leading to a better understanding of the underlying physics.