Chandler said that the results explaining how hydronium and hydroxyl are created in pure water can be extended to any weak acid or base.
"Water is the simplest example of a weak acid or weak base, but when you put some weak acid like an amino acid in water, a minute or an hour later it has given up one of its protons to the bath of water around it," he said.
Chandler and his team calculated these detailed reactions by rethinking statistical mechanics. That branch of physical chemistry deals with the chances of going from one state to another, such as from a neutral molecule in water to an ionized molecule. If this is a very rare event, though - a reaction that occurs a billion times slower than other reactions going on around it - calculating the most likely outcome from the fundamental equations of quantum mechanics would keep a computer busy for the lifetime of the universe.
Instead, they came up with the idea of dealing with what Chandler calls trajectories, that is, the entire dynamic process from one state to another. If each possible state is like a valley in a landscape of valleys and ridges, he said, the trajectory from one valley to another would be like a strong rope stretching over the peaks. To find the easiest trajectory over the ridge to the desired valley, it's quicker to throw ropes over the passes and, learning from your mistakes, narrow the possibilities, than to randomly try all possible ways to scale the ridges.
"After you have thrown these ropes successfully, you march along the ropes, and you feel wha
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Contact: Robert Sanders
rls@pa.urel.berkeley.edu
510-643-6998
University of California - Berkeley
18-Mar-2001