The possibility of bonding clean diamond surfaces covalently in ultrahigh v
acuum is investigated by molecular dynamics simulations based on a tight bi
nding model. Our simulations predict that strong covalent bonding is possib
le for C(001)-2x1 surfaces. C(111)-2x1 surfaces will bond very weakly and d
ebond already at moderate temperatures. (C) 2000 American Institute of Phys
ics. [S0003-6951(00)03027-8].