Anharmonicity and cross section for absorption of radiation by water dimer

摘要: We calculate the absorption cross section of water dimer molecules in thermal equilibrium at temperatures typical lower atmosphere using quantum mechanical coupled nonlinear equations motion. Empirical Morse-oscillator potentials are used to describe local modes monomer, and RWK2 potential is employed for interaction between atoms different monomers. The strong anharmonicity taken into account by an extension molecular dimers methods originally developed lattice dynamics solid helium. Approximations based on exploiting hierarchy energy scales weakly hydrogen-bonded allow determination spectrum over range significant solar radiation, up 20 000 cm−1, including important contributions overtone combination transitions. This approach can tackle complicated task mixing vibrational fundamentals overtones. have found that these vibratio...