Ground-state path integral Monte Carlo simulations of positive ions in $^4$He clusters bubb.pdf

下载文档

2
0
约3.81万字
约 9页
2017-04-09 发布于江苏
举报
版权申诉
保障服务

Ground-state path integral Monte Carlo simulations of positive ions in $^4$He clusters bubb.pdf

1、本文档共9页，可阅读全部内容。
2、有哪些信誉好的足球投注网站（book118）网站文档一经付费（服务费），不意味着购买了该文档的版权，仅供个人/单位学习、研究之用，不得用于商业用途，未经授权，严禁复制、发行、汇编、翻译或者网络传播等，侵权必究。
3、本站所有内容均由合作方或网友上传，本站不对文档的完整性、权威性及其观点立场正确性做任何保证或承诺！文档内容仅供研究参考，付费前请自行鉴别。如您付费，意味着您自己接受本站规则且自行承担风险，本站不退款、不进行额外附加服务；查看《如何避免下载的几个坑》。如果您已付费下载过本站文档，您可以点击这里二次下载。
4、如文档侵犯商业秘密、侵犯著作权、侵犯人身权等，请点击“版权申诉”（推荐），也可以打举报电话：400-050-0827(电话支持时间：9:00-18:30)。

Ground-state path integral Monte Carlo simulations of positive ions in $^4$He clusters bubb

a r X i v : c o n d - m a t / 0 7 0 1 2 1 5 v 1 [ c o n d - m a t .o t h e r ] 1 0 J a n 2 0 0 7 Ground-state path integral Monte Carlo simulations of positive ions in 4He clusters: bubbles or snowballs? Stefano Paolini,1, 2, ? Francesco Ancilotto,1, 2, ? and Flavio Toigo1, 2, ? 1 – Dipartimento di Fisica ”G. Galilei”, Universita’ di Padova, via Marzolo 8, I-35131 Padova, Italy 2 CNR-INFM–DEMOCRITOS National Simulation Center, Trieste, Italy (Dated: February 6, 2008) The local order around alkali (Li+ and Na+) and alkaline-earth (Be+, Mg+ and Ca+) ions in 4He clusters has been studied using ground-state path integral Monte Carlo calculations. We ap- ply a criterion based on multipole dynamical correlations to discriminate between solid-like versus liquid-like behavior of the 4He shells coating the ions. As it was earlier suggested by experimental measurements in bulk 4He, our findings indicate that Be+ produces a solid-like (“snowball”) struc- ture, similarly to alkali ions and in contrast to the more liquid-like 4He structure embedding heavier alkaline-earth ions. PACS numbers: 36.40.-c, 36.40.Mr, 67.40.Yv, 67.70.Jg, 02.70.Ss I. INTRODUCTION In past decades, the implantation of ions in liquid he- lium has often been used to probe the bulk properties of the superfluid state.1 The attention has also focused on the details of the structure of the helium solvent around the ions.2,3,4 As a consequence of electrostriction, a strong increase in the helium density with respect to its bulk value is expected in the surroundings of the impu- rity site.2,3 Within a crude picture, ions in liquid helium can be divided in two categories, on the basis of the dif- ferent local structure they create in the solvent. Strongly attractive ions tend to form a solid-like structure, the so- called snowball, characterized by a very inhomogeneous helium density in the surroundings of the impurity. Al- kali ions are believed to belong to this category. In con- trast, singly charged al