Intense interactions of molecules with a short-wavelength electromagnetic radiation field: I. The fundamentals of the nonadiabatic theory

The intense interactions between short-wavelength (SW) electromagnetic radi ation with a wavelength lambda greater than or equal to 1 Angstrom and inte nsity up to 10(14) W/cm(2) and simple and polyatomic molecules are studied with the coherent excitations of high-lying Rydberg and autoionizing states taken into account. The Hamiltonian of a system "molecule + SW radiation" is obtained by using the methods of quantum electrodynamics. Conditions for the applicability of the dipole approximation to describe the interactions of molecules with radiation of the UV, VUV, XUV, and soft X-ray range are found. The fundamentals of the theory of resonance scattering of SW radiati on from diatomic, triatomic, and symmetric- and asymmetric-top polyatomic m olecules are outlined. (C) 2001 MAIK "Nauka/Interperiodica".