1. IBM Research, Yorktown Heights, New York 10598, United States
2. Department of Mechanical Engineering, University of California, Berkeley, California 94720, United States
3. IBM Research, Av. República do Chile, 330, CEP 20031-170 Rio de Janeiro, RJ, Brazil
4. Department of Organic Chemistry, Instituto de Química, Universidade Federal do Rio de Janeiro, CEP 21941-909 Rio de Janeiro, RJ, Brazil