Decrease In Transition Probability Research Articles

Effect of piezo electric field on emission characteristics in GaN/AlGaN quantum wells

The transition probability has been estimated in strained GaN/AlGaN quantum wells (QWs) taking into account a carrier separation caused by the piezo electric field. It is found that the decrease of transition probability is not significant under high-level carrier injection for weakly strained QWs as high as 0.2%. However, that decrease should be considered in strongly strained QWs as about 1%.

Multiphoton ionization of hydrogen atom in intense laser beam

The transition amplitude corresponding to a transition from the ground state to a final continuum state in the presence of an intense field is evaluated. Results show that the transition probability increases, while the slope of the curve decreases, with the increase in intensity. It is shown that higher order processes are more probable for high intensities, whereas lower order processes dominate for low intensities. It is found that the contribution of the S wave is more than that of other partial waves. Another feature found is the decrease of transition probability with increasing photon energy or decreasing wavelength.

Measured Transition Probabilities for the Schumann-Runge System of Oxygen

Transition probabilities for the Schumann-Runge system of O2 have been measured in absorption in the wavelength region 2650–3900 A. Oxygen was heated in a shock tube to temperatures up to 4500°K, thereby populating high vibrational and rotational levels. Absorption spectra were photographed using a high-speed flash lamp and a large Littrow quartz spectrograph. Transition probabilities for the bands of three sequences, associated with the zero, 1st, and 2nd vibrational levels of the excited electronic state, yield an f value of 0.048±0.008 which, when corrected for wavelength dependence, is about ⅓ that determined in the vacuum ultraviolet. This corresponds to a decrease in transition probability with increasing internuclear separation. Line-width variations with temperature and density have also been measured. The optical diameter for O2–O2 collisions was determined as 6 A and for O2–O collisions as 10 A.