Simple theoretical reasoning and experimental observations are combined to elucidate the properties of pump-probe methods. As a result, a hybrid VADS-TOF technique is developed for measuring correlated internal state energy disposal involving H and its counter-fragment(s). Realistic mathematical model is established for extracting dynamical parameters. The techniques are applied to the photolysis of 2-iodopropane and H2Se. Speed distributions for H atoms resulting from the 193nm photolysis of 2-iodopropane (non-deuterated and deuterated) and iodomethane are measured and compared in order to assign peaks to alpha and beta bond cleavage sites. The measured pulse energy dependence of the signal intensities reveals that H atom formation from alpha-carbon site goes faster than from beta-carbon site. The wavelength dependence of the total and partial dissociation cross-sections and the anisotropy of photolysis of H2Se are measured at ten wavelengths spanning from 193--266 nm. The branching fraction leading to v = 1 of (HSe(2pi 3/2) clearly shows an interesting reactive resonance structure. The opening thresholds of all vibrational channels turn out to be at much higher photon energies than what are expected energetically. The wavelength dependence of the total dissociation cross section is of a different shape than the UV spectrum. Possible dynamic implications of this are briefly discussed. The wavelength dependent anisotropy reveals that, at all wavelengths, mainly the 1B1 state of H2Se is correlated with the HSe( 2pi3/2) channel. For the HSe(2pi 1/2) channel, at shorter wavelengths (220nm), the 1B 1 state is still the main correlating state. At the longer wavelength of 266nm, however, it is the 1B2 state of H 2Se that mainly correlates with it