Picosecond solvation dynamics of alkali cations in superfluidHe4nanodroplets

Antonio Leal, David Mateo, Alberto Hernando, Martí Pi, Manuel Barranco, Alessandro Ponti, Fausto Cargnoni, Marcel Drabbels
2014 Physical Review B  
The dynamics following the photoionization of neutral Rb and Cs atoms residing in a dimple at the surface of a superfluid 4 He 1000 nanodroplet has been investigated within time-dependent density functional theory, complementing a previous study on Ba. The calculations reveal that structured high density helium solvation layers form around both the Rb + and Cs + cation on a picosecond time scale, forming so-called snowballs. In contrast to the Rb + ion, Cs + is not solvated by the 4 He 1000
more » ... y the 4 He 1000 droplet but rather desorbs from it as a Cs + He n snowball. This outcome is partially related to the large size of Cs + cation in relation to the helium droplet as is revealed by calculations performed using a planar helium surface. The large droplet deformations induced by the solvation of the Rb + cation is found to lead to efficient nucleation of quantized vortex loops or rings.
doi:10.1103/physrevb.90.224518 fatcat:jwrq3jek3jf6tpg4mim4dw3lum