Paired molecules store data

As computer storage devices cram more information into ever tinier spaces, researchers working to keep ahead of the curve are looking at the storage possibilities of single molecules.

Binary information can be stored in any medium that has at least two distinct states that can represent the 1s and 0s of computer information and that can be changed, or written, and sensed, or read.

Researchers from the University of California at Irvine have bonded a pair of molecules to form a molecule that has two states. The components are photochromic fulgimide and a dye molecule capable of florescence.

The molecule resists accidental erasure, switches quickly, and could eventually be used to store more than a terabyte of data on a removable disk, according to the researchers.

Particular wavelengths of light cause the molecule to open and close, and thus can write information to a series of molecules. When a molecule is hit with 530-nanometer light it opens, and when it absorbs 400-nanometer light it closes.

Information stored in the molecules can be read without harming the information using a third wavelength -- 650 nanometers. When open molecules absorb this wavelength, they fluoresce at 700 nanometers.

Molecular memory could become practical in five to seven years, according to the researchers. The work appeared in the August 14, 2003 issue of the Proceedings of the National Academy of Sciences.