Doubly Charged Cluster of 1.1-Difluoroethylene: Observation of an Anomalous Critical Size
Abstract
A field of growing interest is the observation of doubly charged molecular cluster ions (Mn2+) generated through electron impact ionization. Current work indicates that these cluster ions are composed of two separate cations generated via two sequential single ionization events of one incoming electron. These doubly charged cluster ions can then be detected through mass spectroscopy, if their size, n, is larger then n2, a critical value where the coulombic repulsion is offset by the cohesive forces of solvation. We present in this communication the first observation of a critical size (n2) of 9 for doubly charged clusters of 1,1-difluoroethylene. This is a highly unusual result in that it is the lowest critical size measured so far (the previous record was n2 = 21 for sulfur dioxide). In addition, this is the first example of a doubly charged cluster where its critical size is not predicted by the Echt scaling law (that the critical size of the doubly charged cluster is proportional to the inverse of the product of Tc and V to the 1/3 power, where Tc is the critical temperature and v is the molecular volume). This suggests that the doubly charged CH2CF2 clusters are packed in a non-spherical arrangement (ie, chains, rings, or stacking of the ethylene planes).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1989
- Accession Number
- ADA207767
Entities
People
- James F. Garvey
- William R. Peifer
Organizations
- University at Buffalo