Chromium nanoparticles are formed using superfluid helium droplets as the nanoreactors, which are strongly ferromagnetic. The transition from antiferromagentism to ferromagnetism is attributed to atomic‐scale disorder in chromium nanoparticles, leading to abundant unbalanced surface spins. Theoretical modeling confirms a frustrated aggregation process in superfluid helium due to the antiferromagnetic nature of chromium.

We report that Au atoms within van der Waals complexes serve as catalysts for the first time. This was observed in ionization-induced chemistry of 1,6-hexanediol-Au and 1,8-octanediol-Au complexes formed in...

Binary clusters containing a large organic molecule and metal atoms have been formed by the co-addition of 5,10,15,20-Tetra(4-pyridyl)porphyrin (H2TPyP) molecules and gold atoms to superfluid helium nanodroplets, and the resulting complexes were then investigated by electron impact mass spectrometry. In addition to the parent ion H2TPyP yields fragments mainly from pyrrole, pyridine and methylpyridine ions because of the stability of their ring structures. When Au is co-added to the droplets the mass spectra are dominated by H2TPyP fragment ions with one or more Au atoms attached. We also show that by switching the order in which Au and H2TPyP are added to the helium droplets, different types of H2TPyP/Au complexes are clearly evident from the mass spectra. This study suggests a new route for the control over the growth of metal-organic compounds inside superfluid helium nanodroplets.3

A safe approach for fabrication silver nanoparticles has established. In this approach a grape fruit peel extract was employed to serve as a capping agent to reduce the aggregation process of Ag nanoparticles. The formation of Ag nanocrystal was confirmed by the color change from yellow to brownish red after 24-hour incubation. The red shift of SPR band position (∼455 nm) compared to the bulk silver (420 nm) indicates the formation of silver nanoparticles. The size and morphology of Ag nanoparticles were characterized by scanning electron microscopy. The SEM images revealed that the prepared Ag nanoparticles have a diameter of 50-70 nm, while the cubic-like shapes are dominated. Fourier Transform Infrared Spectroscopy (FT-IR) was employed to characterize the prepared Ag nanoparticles.