On the possibility of bremsstrahlung-isochromat spectroscopy for gas-phase molecules

Experimental and theoretical possibilities for X-ray bremsstrahlung-isochromat spectroscopy of gas-phase molecules are considered. It is argued that sufficient bremsstrahlung intensity can be obtained with the use of high-intensity monochromators developed for X-ray photoelectron spectroscopy and with electron optics for gas-phase X-ray emission spectroscope. Transition amplitudes and intensities for the process are formulated using general many-electron wavefunctions for bound states and assuming strong orthogonality between the wavefunction of the incoming electron and the neutral ground state. The role of correlation and relaxation effects is analyzed and analogies to the theory of photoionization utilized in a discussion of possible experimental effects.