Vibrational spectroscopy distinguishes different diffusing isotopes

Japanese researchers have pushed chemists’ ability to identify substances by studying their bond vibrations to a new atomic-resolution frontier. Ryosuke Senga from the National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, and colleagues combine scanning transmission electron microscopy (Stem) and vibrational spectroscopy to distinguish atoms of different carbon isotopes in a growing graphene sample.

‘This method can provide isotopic maps at atomic scale without destroying the sample,’ explains Senga. This contrasts with mass spectroscopy, which can also detect isotopes with high sensitivity but can measure each sample only once, he adds. Stem is therefore better for tracing a ‘process or reaction in which multiple measurements at the same place are necessary’, says Senga.