$TDHFX group (relevant for SCF=RHF if RUNTYP=TDHFX) This group permits the analytical determination of static and/or frequency dependent polarizabilities and hyperpolarizabilities (alpha, beta, and gamma), as well as their first- and second-order geometrical derivatives (of alpha and beta). This permits the prediction of dynamic (nonresonant) Raman and hyper-Raman spectra, yielding both intensities and depolarizations. The method is only available for closed shell systems (RHF). For other polarizability options, see $FFCALC and $TDHF. For ordinary Raman spectra, see $RAMAN. You must not use point group symmetry in this kind of calculation (except to enter the molecule's structure), so provide NOSYM=1. Since the derivative level is quite high, it is a good idea to converge the SCF problem crisply, CONV=1.0D-6. These options are not forced by the RUNTYP, so please use explicit input. The $TDHFX group acts as a script. Each keyword must be on a separate line, terminated by a $END. The available keywords are gathered into 3 sets. Those belonging to the first set must appear before the second set, which must appear before the third set. Set 1: Here is a list of keywords that specifies the number of parameters (electric fields and geometrical distortions) that will be taken into account in the computations. ALLDIRS = compute the responses for all the electric field directions (x,y,z). DIR idir = compute the responses for one electric field specific direction: x(idir=1), y(idir=2) and z(idir=3). USE_C = do the computation in Cartesian coordinates. USE_Q = do the computation in normal coordinates. The default is ALLDIRS and USE_C. Set 2: The following two keywords must be specified before any computation that requires vibrational frequencies or normal modes of vibration: FREQ = compute the normal modes and the harmonic vibrational frequencies. Do a HESSIAN job. FREQ2 = same as FREQ but store the second derivative of the monoelectronic Hamiltonian. Required if you want to determine geometrical second-order derivatives of properties. Set 3: The following keywords are related to the generalized iterative method to solve TDHF mixed derivative equations. They can be inserted anywhere in the $TDHFX group and change the behavior of the generalized iterative method for any of the following tasks that might be requested. DIIS = Use the DIIS method. This is the default method. NOACCEL = Do not use any accelerating method. ITERMAX imax = Specify the maximum number of iterations to obtain the converged solution. Default=100. CONV threshold = the threshold convergence criterion for the U response matrices. Default=1E-5. Below are the keywords to select a particular computation. The xx_NI version will call a non-iterative procedure. The laser energy (w) must be given in Hartree. Divide by 219,474.6 to convert a frequency in wavenumbers (cm-1) to a photon energy in Hartree. Wavelength (in nm) is 45.56/w, when w is in Hartree. Static polarizabilities may be obtained from w=0.0. MU = compute the dipole moment. ALPHA w = compute the dynamic polarizability: alpha(-w;w). BETA w1 w2 / BETA_NI w1 w2 = compute the dynamic first hyperpolarizability: beta(-w1-w2;w1,w2). GAMMA w1 w2 w3 / GAMMA_NI w1 w2 w3 = compute the dynamic second hyperpolarizability: gamma(-w1-w2-w3;w1,w2,w3). POCKELS w / POCKELS_NI w = compute electro-optic Pockels effect: beta(-w;w,0). OR w / OR_NI w = optical rectification: beta(0;w,-w). SHG w / SHG_NI w = second harmonic generation: beta(-2w;w,w). KERR w / KERR_NI w = DC Kerr effect: gamma(-w;w,0,0). ESHG w / ESHG_NI w = electric field induced 2nd harm gen: gamma(-2w;w,w,0). THG w / THG_NI w = third harmonic generation: gamma(-3w;w,w,w). DFWM w / DFWM_NI w = degenerate four wave mixing gamma(-w;w,-w,w). See the review D.P.Shelton, J.E.Rice Chem.Rev. 94, 3-29(1994) for more information on the quantities just above. The next options are nuclear derivatives of some of the above. DMDX_NI = compute the dipole derivative matrix, the geometrical first derivative of MU. DADX w / DADX_NI w = compute the polarizability derivative matrix, the geometrical first-order derivative of alpha(-w;w). DBDX w1 w2 / DBDX_NI w1 w2 = compute the geometrical first-order derivative of beta(-w1-w2;w1,w2). D2MDX2_NI = compute geometrical second derivatives of MU D2ADX2_NI w = compute geometrical second derivatives of alpha(-w;w). D2BDX2_NI w1 w2 = geometrical second derivatives of beta(-w1-w2;w1,w2). The next two keywords automatically select paths through the package generating the required intermediates (both polarizabilities and their nuclear derivatives) to form spectra. The most efficient path through the program will be selected automatically. RAMAN w = Summarize the Raman responses in a table, and if necessary, compute the geometrical first-order derivatives of alpha(-w;w). HRAMAN w = Summarize the hyper-Raman responses in a table, and if necessary, compute the geometrical first- order derivatives of beta(-2w;w,w). The following keywords permit the deletion of disk files associated with the set of frequencies w1,w2,... FREE w1 FREE w1 w2 FREE w1 w2 w3 Below is an example of a TDHFX group: $TDHFX ALLDIRS USE_Q FREQ DIIS ITERMAX 100 CONV 0.1E-7 HRAMAN 0.02 FREE 0.02 FREE 0.02 0.02 HRAMAN 0.03 $END References: "Time Dependent Hartree-Fock schemes for analytic evaluation of the Raman intensities" O.Quinet, B.Champagne J.Chem.Phys. 115, 6293-6299(2001). "Analytical TDHF second derivatives of dynamic electronic polarizability with respect to nuclear coordinates. Application to the dynamic ZPVA correction." O.Quinet, B.Champagne, B.Kirtman J.Comput.Chem. 22, 1920-1932(2001). "Analytical time-dependent Hartree-Fock schemes for the evaluation of the hyper-Raman intensities" O.Quinet, B.Champagne J.Chem.Phys. 117, 2481-2488(2002). errata: JCP 118, 5692(2003) "Analytical time-dependent Hartree-Fock evaluation of the dynamically zero-point averaged (ZPVA) first hyperpolarizability" O.Quinet, B.Kirtman, B.Champagne J.Chem.Phys. 118, 505-513(2003). Computer quirks: 1. This package uses file numbers 201, 202, ... but some compilers (chiefly g77) may not support unit numbers above 99. The remedy is to use a different computer or compiler. 2. If you experience trouble running this package under AIX, degrade the optimization of subroutine JDDFCK in hss2b.src, by placing this line @PROCESS OPT(2) immediately before JDDFCK, recompile hss2b, and relink. ========================================================== ==========================================================

generated on 7/7/2017