Knowledge Bank

We have previously shown that $CS2$ continuum-like emission persists under collision free conditions both in a bulb and in a supersonic $et.1$ Here we explore the range of excitation wavelengths over which this emission is excited, the ratio of continuum to discrete emission in this range and the lifetimes associated with the continuum emission. Continuum emission is excited by 340 nm radiation; it is weak compared to discrete emission when the excitation is in band regions. As the excitation moves to shorter wavelengths, continuum emission becomes more intense relative to discrete. It is excited at all wavelengths, even between bands. When individual rotational lines of V system bands are excited, continuum as well as discrete emission is always observed. It becomes predominant when the excitation wavelength is less than 300 mm and at 280 mm it alone is present; discrete emission is no longer present. The lifetime associated with continuum emission is long compared to that of the discrete. It lengthens significantly to over 20 usec as the excitation shifts to shorter wavelengths.