CAS SCF/CI calculations of low-lying states and potential energy surfaces of Si3

✍ Scribed by K. Balasubramanian

• Publisher: Elsevier Science
• Year: 1986
• Tongue: English
• Weight: 607 KB
• Volume: 125
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(86)85180-6

✦ Synopsis

Complete active space MC SCF and restricted first-order CI calculations of low-lying states of Si, ('A,, 3Br, 'Br, 3B,, 'Bi, 3A2, 'A,) and potential energy surfaces of the 'A, and 3Br states are calculated. MRSDCI calculations are carried out for the 'A, and 'A\ (D3k) states. The ground state of Si, is found to be the 'A, state with the 3A'r (equilateral triangle) state 3.6 kcal/mole above the singlet state in a TZ + Id basis set. A second shallow minimum (obtuse triangle, apex angle 160") and a barrier are found in the potential energy surface of the 'Br state. The equilibrium geometry of the 'A, state is an isosceles triangle, apex angle 80" while that of the 3B, (3Afr) state is an equilateral triangle, The equilateral and isosceles triangular structures are more stable than the corresponding linear structures.