To summarize the main features of Q-Chem’s ground state self-consistent field capabilities, the user needs to consider:
Input a molecular geometry ($molecule keyword)
Cartesian
Z-matrix
Read from prior calculations
Declare the job specification ($rem keyword)
JOBTYPE
Single point
Optimization
Frequency
See Table 4.1 for further options
METHOD
Single method specification for exchange and correlation. Alternatively these can be specified separately.
EXCHANGE
Linear scaling algorithms for all methods
Arsenal of exchange density functionals
User definable functionals and hybrids
CORRELATION
DFT or wave function-based methods
Linear scaling (CPU and memory) incorporation of correlation with DFT
Arsenal of correlation density functionals
User definable functionals and hybrids
See Chapter 6 for wave function-based correlation methods.
Exploit Q-Chem’s special features
CFMM, LinK large molecule options
SCF rate of convergence increased through improved guesses and alternative minimization algorithms
Explore novel methods if desired: CASE approximation, PAOs.