Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
pes_generators [2021/09/08 06:43]
rauhutmoschneide [Options]
pes_generators [2022/02/28 08:35] (current)
rauhutmoschneide [Scaling of individual coordinates]
Line 292: Line 292:
 The ''SCALE'' option of the ''SURF'' program enables a modification of the extension of all difference potentials by a common factor. In contrast to that the ''SCALNM'' directive allows for the scaling with respect to the individual normal coordinates. This is the recommended choice for potentials dominated by quartic rather than quadratic terms. At most 3N-6 individual scale factors and shift parameters can be provided. In particular the ''AUTO'' option was found to be very helpful in practical applications. The ''SCALE'' option of the ''SURF'' program enables a modification of the extension of all difference potentials by a common factor. In contrast to that the ''SCALNM'' directive allows for the scaling with respect to the individual normal coordinates. This is the recommended choice for potentials dominated by quartic rather than quadratic terms. At most 3N-6 individual scale factors and shift parameters can be provided. In particular the ''AUTO'' option was found to be very helpful in practical applications.
  
-  * **''AUTO''=//on / off//** ''AUTO''=//on// (defaulr) switches on an automatic scaling procedure of the potential in order to determine meaningful elongations and ''SHIFT'' values with respect to all coordinates, i.e. for each normal mode an optimized scaling parameter ''SFAC'' and ''SHIFT'' parameter will be determined. Usually this results in an increased number of 1D grid points. The ''AUTO'' keyword intrinsically depends on the thresholds and parameters, which can be controlled by the keywords ''THRSHIFT'', ''ITMAX'', ''LEVMAX'', ''DENSMAX'', and ''DENSMIN''.+  * **''AUTO''=//on / off//** ''AUTO''=//on// (default) switches on an automatic scaling procedure of the potential in order to determine meaningful elongations and ''SHIFT'' values with respect to all coordinates, i.e. for each normal mode an optimized scaling parameter ''SFAC'' and ''SHIFT'' parameter will be determined. Usually this results in an increased number of 1D grid points. The ''AUTO'' keyword intrinsically depends on the thresholds and parameters, which can be controlled by the keywords ''THRSHIFT'', ''ITMAX'', ''LEVMAX'', ''DENSMAX'', and ''DENSMIN''.
   * **''DENSMAX''=//value//** Threshold for the maximum vibrational density on the edges of the potential needed for the automated upscaling of the potentials (see keyword ''AUTO'').   * **''DENSMAX''=//value//** Threshold for the maximum vibrational density on the edges of the potential needed for the automated upscaling of the potentials (see keyword ''AUTO'').
   * **''DENSMIN''=//value//** Threshold for the minimum vibrational density on the edges of the potential needed for the automated downscaling of the potentials (see keyword ''AUTO'').   * **''DENSMIN''=//value//** Threshold for the minimum vibrational density on the edges of the potential needed for the automated downscaling of the potentials (see keyword ''AUTO'').
Line 491: Line 491:
 ==== Options ==== ==== Options ====
  
 +    **''AUTOFIT''=//n//** (=0 Default) If ''AUTOFIT''=1, the number of basis function for fitting the grid points is determined automatically. To do so, the fine grid of the energy is compared to the coarse grid points. If the deviation is too high, another basis function is added. The procedure starts with 8 basis functions and stops at the latest at ''FITXD_MAX'' basis functions. Once 'AUTOFIT' is used, the keywords ''FITXD'' does not have any use.
   * **''CORRECT''=//n//** (=1 (on) Default) If a certain subsurface does not converge despite increasing the number of ab initio calculations, symmetry in this subsurface (if any) will be neglected in order to avoid any errors due to inaccuracies in the displacement vectors and the subsurface will be recalculated accordingly. This option is automatically switched off in any Taylor expansions of the PES.   * **''CORRECT''=//n//** (=1 (on) Default) If a certain subsurface does not converge despite increasing the number of ab initio calculations, symmetry in this subsurface (if any) will be neglected in order to avoid any errors due to inaccuracies in the displacement vectors and the subsurface will be recalculated accordingly. This option is automatically switched off in any Taylor expansions of the PES.
 +  * **''FITXD_MAX''=//n//**(=10 Default) For the automated procedure with ''AUTOFIT'' an upper limit for the number of basis functions can be set with this keyword.
   * **''FITMETHOD''=//n//** (=1 Default) Within the iterative build-up of the individual subsurfaces, intermediate fitting will be used. This can be based on true multidimensional Kronecker product fitting (''FITMETHOD''=1) or on fitting along one-dimensional cuts (''FITMETHOD''=2).   * **''FITMETHOD''=//n//** (=1 Default) Within the iterative build-up of the individual subsurfaces, intermediate fitting will be used. This can be based on true multidimensional Kronecker product fitting (''FITMETHOD''=1) or on fitting along one-dimensional cuts (''FITMETHOD''=2).
-  <!--*  **''FINALFIT''=//n//** (=2 Default) Similar to ''FITMETHOD''. The difference: ''FINALFIT'' defines the fit method for transforming the //ab initio// grid to the fine grid. --> 
   * **''INFO''=//n//** (=1 Default) ''INFO''=0 suppresses any information about the program parameters and symmetry information. ''INFO''=1 refers to the standard output, while ''INFO''=2 provides additional information about the symmetry recognition.   * **''INFO''=//n//** (=1 Default) ''INFO''=0 suppresses any information about the program parameters and symmetry information. ''INFO''=1 refers to the standard output, while ''INFO''=2 provides additional information about the symmetry recognition.
   * **''LOWERDIM''=//n//** (=2 Default) In order to determine energy differences for the subsurfaces, contributions of subsurfaces of lower order need to be substracted from those of current order. The lower order energy contribution can be determined in three different ways: ''LOWERDIM''=1 determines these contributions from explicit electronic structure calculations, ''LOWERDIM''=2 uses Kronecker product fitting of the lower order terms and ''LOWERDIM''=3 retrieves this information from the intermediate fine grid representation of the underlying subsurfes.   * **''LOWERDIM''=//n//** (=2 Default) In order to determine energy differences for the subsurfaces, contributions of subsurfaces of lower order need to be substracted from those of current order. The lower order energy contribution can be determined in three different ways: ''LOWERDIM''=1 determines these contributions from explicit electronic structure calculations, ''LOWERDIM''=2 uses Kronecker product fitting of the lower order terms and ''LOWERDIM''=3 retrieves this information from the intermediate fine grid representation of the underlying subsurfes.
Line 512: Line 513:
   * **''THRSED''=//value//** (=1.0d-6 Default) Threshold for determining symmetry elements of the molecule.   * **''THRSED''=//value//** (=1.0d-6 Default) Threshold for determining symmetry elements of the molecule.
   * **''THRSYMx''=//value//** ($x$=1,2,...) Threshold used for recognizing symmetry within a subsurface of the PES expansion - in dependence on the order of the expansion term. The defaults are ''THRSYM1''=5.0d-5, ''THRSYM2''=1.0d-5,''THRSYM3''=5.0d-6,''THRSYM4''=5.0d-6,''THRSYM5''=1.0d-7.   * **''THRSYMx''=//value//** ($x$=1,2,...) Threshold used for recognizing symmetry within a subsurface of the PES expansion - in dependence on the order of the expansion term. The defaults are ''THRSYM1''=5.0d-5, ''THRSYM2''=1.0d-5,''THRSYM3''=5.0d-6,''THRSYM4''=5.0d-6,''THRSYM5''=1.0d-7.
 +  * **''DELAUTO''=//variable//**(=//off// Default) If ''DELAUTO''=//on//, all not converged surfaces of the highest considered dimension are deleted. It only works after a restart from an external potfile.
  
 ==== Selection of Modes ==== ==== Selection of Modes ====
Line 519: Line 520:
 The ''VIBMODE'' directive allows to span the PES only with predefined modes. The following options can be combined in various ways. The ''VIBMODE'' directive allows to span the PES only with predefined modes. The following options can be combined in various ways.
  
 +  * **''ENERGHIGH''=//x//** Modes with a frequency lower than **x** are used to span the surface (according to the harmonic frequencies)
 +  * **''ENERGLOW''=//x//** Modes with a frequency higher than **x** are used to span the surface (according to the harmonic frequencies)
 +  * **''HIGH''=//n//** the highest **n** modes are used to span the surface
 +  * **''LOW''=//n//** the lowest **n** modes are used to span the surface
   * **''MODE''=//n//** Mode which is used to span the surface (can be used multiple times)   * **''MODE''=//n//** Mode which is used to span the surface (can be used multiple times)
-  * **''LOW''=//n//** the lowest **n** modes are used to span the surface 
-  * **''HIGH''=//n//** the highest **n** modes are used to span the surface 
-  * **''ENERGLOW''=//x//** Modes with a frequency higher than **x** are used to span the surface (according to the harmonic frequencies) 
-  * **''ENERGHIGH''=//x//** Modes with a frequency lower than **x** are used to span the surface (according to the harmonic frequencies) 
- 
- 
 ==== Visualisation and interfaces ==== ==== Visualisation and interfaces ====
  
Line 749: Line 748:
   * **''MEMORY''=//n//** Memory request of the individual single point calculations in MW.   * **''MEMORY''=//n//** Memory request of the individual single point calculations in MW.
   * **''WFU''=//file name//** If additional information need to be read in from a .wfu file, this can be specified here.   * **''WFU''=//file name//** If additional information need to be read in from a .wfu file, this can be specified here.
 +