Direct Lifetime Measurement of Laser-Excitedn=3Levels in Para-H2

Abstract

This paper reports measurements of the lifetimes of fourteen levels in the 3s, 3d complex of para-H 2 by a delayed coincidence method. A collimated beam of metastable hydrogen molecules was selectively excited by light pulses from a cw dye laser and fluorescent radiation was detected by a vacuum ultraviolet photo multiplier. The observed lifetimes range from 11.1 to 48.8 nsec. Similar methods can be used to determine the structure and lifetimes in other excited states of H 2 and in a variety of other systems.

Radiative lifetime measurements for H2 molecule

“…As can be seen in table II a good agreement is found with levels measured recently [12,15]. To our knowledge no theoretical results for comparison exist.…”

“…-Results for triplet states from this work and those from references [6,12,15] are shown in table II. The electronic transitions used in the presented work can be seen in the figure 3. For all of the studied levels no pressure dependence was found for the measured lifetimes in our experimental range.…”

“…Radiative lifetime measurements for H2 molecule were first reported by Cahill [6] using a delayedcoincidence method (DCM). This method [7] has been employed by many other authors with different excitation processes : electron excitation [8][9][10][11], combined electron-laser excitation [12], or with selected VUV light from a synchrotron radiation source [13]. Other techniques have also been used : Miller et al [14][15] carried out lifetime measurements with a MOMRIE (microwave optical magnetic resonance induced by electrons) technique and Chien et al [16] used Hanle effect.…”

“…Other techniques have also been used : Miller et al [14][15] carried out lifetime measurements with a MOMRIE (microwave optical magnetic resonance induced by electrons) technique and Chien et al [16] used Hanle effect. For triplet states only Eyler et al [12] measured systematically the radiative lifetimes of levels with (ls3d) and (ls3s) electronic configuration.…”

Molecular hydrogenn=3 triplet gerade complex disentangled

“…The experimental data were taken from Eyler and Pipkin, who were the first to excite n =3 triplet levels with visible light, using a metastable hydrogen beam[20]. lifetime is calculated as the reciprocal transition rate (or Einstein A coefficient for spontaneous FIG 4…”