Accession Number:

ADA247052

Title:

Molecular Interactions and Properties with Many-Body Methods

Descriptive Note:

Annual technical rept. 1 Dec 1990-30 Nov 1991

Corporate Author:

FLORIDA UNIV GAINESVILLE QUANTUM THEORY PROJECT

Personal Author(s):

• Bartlett, Rodney J.

Report Date:

1992-01-21

Pagination or Media Count:

8.0

Abstract:

The crucial component needed to understand molecular reactions is the potential energy surfaces PES that serve to describe the attractions among the atoms and molecules. However, such information is not easy to obtain. In many cases, the most direct approach to obtaining accurate potential surfaces for molecules, and detailed information about their excited states, vibrational spectra, and a wealth of other quantities, is high level ab initio solutions of the Schrodinger equation. However, more so than in most other areas, the ability to provide reliable quantum mechanical results for increasingly large molecules depends critically on improved method development. Whereas supercomputers can enable us to make much larger computations with old methods, the simultaneous development of new methods can increase computational capability by further orders of magnitude. In this regard, many-body perturbation theory MBPT and its infinite-order extensions termed coupled-cluster CC methods offer a number of attractive features that the more traditional configuration interaction approaches lack. Under AFOSR support, we have established these CCMBPT theories as being among the most accurate available, and have developed very efficient and generally applicable computer programs to perform CCMBPT calculations. Also, we have employed these methods for the first time in large-scale ab initio calculations of potential energy surfaces. The successes of our original work in this effort have been substantial see previous AFOSR reports.

Descriptors:

• *COMPUTER PROGRAMS
• COMPUTATIONS
• REACTION KINETICS
• INTERACTIONS
• MOLECULES
• QUANTUM THEORY
• ACCURACY
• ATOMS
• SURFACES
• RELIABILITY
• CONFIGURATIONS
• PERTURBATION THEORY
• SUPERCOMPUTERS
• POTENTIAL ENERGY
• MOLECULAR PROPERTIES
• SCHRODINGER EQUATION
• N BODY PROBLEM
• VIBRATIONAL SPECTRA

Subject Categories:

• Physical Chemistry
• Atomic and Molecular Physics and Spectroscopy

Distribution Statement:

APPROVED FOR PUBLIC RELEASE