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Revision 40 as of 2014-09-27 07:11:48

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RESP module for response properties based on HF and DFT

Contents

  1. RESP module for response properties based on HF and DFT
    1. Keywords for general information
      1. IPRT
      2. NPRT
      3. CHCK
      4. CTHRD
    2. Keyworks for processing excited-state information
      1. METHOD
      2. NFILES
    3. Keyword for geometric derivatives
      1. GEOM: NORDER
    4. Keywords for linear response calculations
      1. LINE
      2. REDUCED
      3. POLA: AOPER, BOPER, BFREQ
    5. Keywords for quadratic response calculations
      1. QUAD
      2. HYPE: AOPER, BOPER, BFREQ, COPER, CFREQ
      3. SINGLE:STATES
      4. DOUBLE: PAIRS
      5. FNAC
      6. NORESP
    6. Keywords for finite difference calculations
      1. FDIF
      2. STEP
      3. BOHR
      4. IGNORE
  2. Quick guides by examples
  3. Some caveats before using this module
      1. dft
      2. scf
      3. tddft

Keywords for general information

IPRT

Print level, >1 gives more information, >2 give more information about integral evaluations.

NPRT

CHCK

Check the interface with several external packages.

CTHRD

Keyworks for processing excited-state information

METHOD

=1, ground state gradients; =2, excited-state calculations which will load TD-DFT output.

NFILES

Linked with istore value in TD-DFT input for loading output.

Keyword for geometric derivatives

GEOM: NORDER

GEOM enables geometric derivatives, NORDER=1, gradient and fo-NACMEs; =2, hessian (not implemented yet.)

Keywords for linear response calculations

LINE

Enable linear response

REDUCED

Solve the response equation in its reduced form [(A-B)(A+B)-w2](X+Y)=Rvo+Rov (not preferred).

POLA: AOPER, BOPER, BFREQ

Polarizabiity: <<A;B>>(wB), where the operators A and B can be dipole (DIP), quadruple (QUA), SOC (HSO), EFG.

Keywords for quadratic response calculations

QUAD

Enable quadratic response function (QRF) calculations

HYPE: AOPER, BOPER, BFREQ, COPER, CFREQ

Hyperpolarizability: <<A;B,C>>(wB,wC)

SINGLE:STATES

Single residue of QRF, STATES can be used to specify the number of states followed by a detailed specification via the triple (ifile,isym,istate).

DOUBLE: PAIRS

Double residue of QRF, PAIRS can be used to specify the number of pairs followed by a detailed specification via two triples (ifile,isym,istate,jfile,isym,jstate).

FNAC

First-order nonadiabatic couplings

NORESP

Neglect the response part of transition density matrix in DOUBLE and FNAC calculations (recommended)

Keywords for finite difference calculations

FDIF

Enable finite difference calculations

STEP

followed by a real number for the step size, default 0.001 [unit].

BOHR

The default unit is angstrom, to use bohr. This keyword must be specified.

IGNORE

Ignore the recomputation of excitation energies for check consistency.

Quick guides by examples

The following examples give the minimal inputs for starting response calculations (Input files and benchmark results can be found in bdf-pkg/tests/input/resp2014):

  1. Ground-state geometric derivatives

  2. Excited-state properties based on analytic derivatives

  3. Response properties based on linear and quadratic response functions

  4. First-order nonadiabatic couplings

  5. Alternative of TD-DFT: particle-particle TDA (pp-TDA) based properties

Some caveats before using this module

dft

1. Thresholds in dft_prescreen.F90 have been set very tight.

2. Keyword ixcfun in SCF allows to use original XC library (default) or XCFun lib (=1) by Ulf Ekström [http://www.admol.org/xcfun] in dft and tddft.

scf

1. Tight convergence on density matrix is required (10-14).

2. sgnfix: fix adjacent sign of MOs during SCF iterations

2. iaufbau=3: fix ordering and sign with respect to the initial MOs.

tddft

1. Tight convergence on eigenvectors (10-8).

2. Keyword lefteig for storing left eigenvectors in TD-DFT

3. Keyword istore speficify the file number of TD-DFT calculations