Spectroscopy in, on, and off a Beam of Superfluid Helium Nanodroplets

摘要: Helium nanodroplet isolation (HENDI) spectroscopy involves the use of a beam He n (103 < 105) nanodroplets which are doped while passing, largely undeflected, through pick-up cell containing low pressure vapor substance to be examined. The carry dopant species downstream, where they can spectroscopically interrogated. After briefly reviewing field and providing few examples applications, in this paper we show that HENDI is also useful producing collimated beams cold, gas-phase molecules which, after forming on cold droplet’s surface, spontaneously desorb from it at very velocities. As desorption velocity added relatively large average droplets, desorbed fly forward as part main used obtain sub-doppler high resolution spectra. Three applications new technique will reported here showing spectrum well known molecule (ground state Na2), less (lowest triplet Na2) third tentatively assigned yet unknown molecule: Na2 He.