Thursday, June 10, 1999 Published at 18:10 GMT 19:10 UK
Scientists see atoms in diamond
Carbon atoms: Each is less than a billionth of a metre in size
By BBC News Online Science Editor Dr David Whitehouse
Unprecedented images of the carbon atoms in a diamond have been taken. The atoms are less than one ten-billionth of a meter apart.
The remarkable images were obtained with a new design of electron microscope at the Lawrence Berkeley National Laboratory (LBNL), US.
Electron microscopes can see things which are invisible to conventional optical microscopes.
This is because a microscope's power depends upon the wavelength of probe it uses. Electrons can be made to behave as if they have a wavelength far smaller than light and hence they can see much smaller objects - such as atoms.
Little and large
The advanced microscope has made it possible, for the first time, to see nitrogen atoms near more massive gallium atoms in gallium nitride.
"The ability to make images of light elements such as carbon, nitrogen, and oxygen in solids at atomic resolution is a very big step forward," says Christian Kisielowski of LBNL.
Michael O'Keefe, also at LBNL says: "Seeing small atoms at atomic resolution has always been a challenge, because they don't strongly scatter the electrons in the microscope's beam."
"When light atoms are close to heavy ones, it has been virtually impossible to see them. Heavy atoms scatter electrons much more, and as a result the pattern is just too complex to resolve," says Dr O'Keefe.
Dr Kisielowski explains that the new electron microscope combined with advanced image processing overcomes this problem.
Uli Dahmen, head of the National Centre for Electron Microscopy at LBNL, says: "We have reached a very important milestone and passed what has been a barrier for electron microscopists worldwide. I can't wait to see what new discoveries it will bring for our users."