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*-matrixRead from prior calculations

Declare the job specification (

*$rem*keyword)JOBTYPE

Single point

Optimization

Frequency

See Table 4.1 for further options

BASIS

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.