Types of Coupled-cluster Methods
The classification of traditional coupled-cluster methods rests on the highest number of excitations allowed in the definition of . The abbreviations for coupled-cluster methods usually begin with the letters "CC" (for coupled cluster) followed by
- S - for single excitations (shortened to singles in coupled-cluster terminology)
- D - for double excitations (doubles)
- T - for triple excitations (triples)
- Q - for quadruple excitations (quadruples)
Thus, the operator in CCSDT has the form
Terms in round brackets indicate that these terms are calculated based on perturbation theory. For example, a CCSD(T) approach simply means:
- A coupled-cluster method
- It includes singles and doubles fully
- Triples are calculated non-iteratively.
Read more about this topic: Coupled Cluster
Famous quotes containing the words types of, types and/or methods:
“Science is intimately integrated with the whole social structure and cultural tradition. They mutually support one other—only in certain types of society can science flourish, and conversely without a continuous and healthy development and application of science such a society cannot function properly.”
—Talcott Parsons (1902–1979)
“Science is intimately integrated with the whole social structure and cultural tradition. They mutually support one other—only in certain types of society can science flourish, and conversely without a continuous and healthy development and application of science such a society cannot function properly.”
—Talcott Parsons (1902–1979)
“The greatest part of our faults are more excusable than the methods that are commonly taken to conceal them.”
—François, Duc De La Rochefoucauld (1613–1680)