# 4.2.31. MCKINLEY (a.k.a. DENALI)¶

## 4.2.31.1. Description¶

This program calculates the second and first order derivatives used for calculating second order derivatives of the energies with perturbation dependent basis sets for SCF and CASSCF wavefunctions. Vibronic frequencies are calculated by the MCLR program which MCKINLEY will start automatically.

MCKINLEY is written such that properties can be computed for any kind of valence basis function that SEWARD will accept. Note, that MCKINLEY can’t handle ECP type basis sets.

MCKINLEY is able to compute the following integral derivatives:

overlap integrals,

kinetic energy integrals,

nuclear attraction integrals,

electron repulsion integrals,

external electric field integrals,

MCKINLEY employs two different integration schemes to generate the one- and two-electron integral derivatives. The nuclear attraction and electron repulsion integrals are evaluated by a modified Rys–Gauss quadrature [96]. All other integral derivatives are evaluated with the Hermite–Gauss quadrature. The same restriction of the valence basis sets applies as to SEWARD. None of the integral 2nd derivatives are written to disk but rather combined immediately with the corresponding matrix from the wavefunction. Integral 1st derivative information is preprocessed and written to disc for later use in MCLR.

Note that MCKINLEY for frequency calculations normally automatically starts the MCLR with a default input. To override this check the keyword NOMClr.

At present the following limitations are built into MCKINLEY:

Max number of unique basis functions: |
2000 |

Max number of symmetry independent centers: |
500 |

Highest angular momentum: |
15 |

Highest symmetry point group: |
\(D_{2h}\) |

## 4.2.31.2. Dependencies¶

MCKINLEY depends on the density, Fock matrices and Molecular orbitals generated by SCF or RASSCF. In addition it needs the basis set specification defined in SEWARD. These dependencies, however, are totally transparent to the user.

## 4.2.31.3. Files¶

### 4.2.31.3.1. Input files¶

MCKINLEY will use the following input files: RYSRW, ABDATA, RUNFILE (for more information see Section 4.1.1.2).

### 4.2.31.3.2. Output files¶

In addition to the standard output unit MCKINLEY will generate the following files.

- MCKINT
File with information needed by the MCLR response program.

## 4.2.31.4. Input¶

Below follows a description of the input to MCKINLEY.

The input for each module is preceded by its name like:

```
&MCKINLEY
```

Optional keywords

- ONEOnly
Compile only the nuclear repulsion and one-electron integrals contribution. The default is to compute all contributions.

- CUTOff
Threshold for ignoring contributions follows on the next line. The default is 1.0D-7. The prescreening is based on the 2nd order density matrix and the radial overlap contribution to the integral derivatives.

- SHOWHessian
The Hessian contributions will be printed.

- PERTurbation
This keyword takes one of the arguments HESSian or GEOMetry on the following line. HESSian makes MCKINLEY compute the full geometrical Hessian, which is required for a subsequent calculation of the vibronic frequencies with the MCLR program. GEOMetry calculates only those parts of the geometrical Hessian that correspond to symmetry allowed displacements (could be used in a second order geometry optimization). The default is to compute the Hessian for vibrational frequency calculations. Note that in the case of numerical differentiation only symmetry allowed displacements will be computed regardless of this keyword.

- NOMClr
Request that this calculation is not followed by the execution of the MCLR module.

- VERBose
The output will be a bit more verbose.

The following is an example of an input which will work for almost all practical cases.

```
&MCKINLEY
Perturbation
Hessian
```