Vibrational energy levels of oxygen in silicon up to one-A(2u)-phonon plusone-A(1g)-phonon states

We have measured infrared absorptions by the Si-O-Si centers in the 600- an d 1800-cm(-1) regions. Besides the previously reported lines at 648.2 and s imilar to 658 cm(-1), we observed the new lines at 668.0, 588.4, similar to 580, and similar to 571 cm(-1), and the silicon isotope lines at 643.2 and 638.5 cm(-1). We also found a new line at 1831.3 cm(-1). We assigned these lines to the transitions from the lower energy levels that had been fixed previously, to find two new groups of energy levels belonging to the one-A( 1g)-phonon state and the one-A(1g)-phonon plus one-A(2u)-phonon state, resp ectively. This indicates that the A(1g)-mode coupling, as well as the A(2u) -mode coupling, is essential for describing the total energy levels. The tr ansitions causing the lines around 600cm(-1) create an A(1g) phonon, exciti ng or deexciting the 30-cm(-1) mode of the oxygen, and those causing the li nes around 1800 cm(-1) simultaneously excite the A(1g) phonon, the A(2u) ph onon, and the 30-cm(-1) mode. (C) 2001 Elsevier Science B.V. All rights res erved.