Different approaches for charge derivation can be followed by using the PyRED program.

- Each charge model is characterized by a keyword (see the System.config file and the 'CHR_TYP' keyword):


  -1- RESP-A1
HF/6-31G*//HF/6-31G* (1) - Connolly surface algo. used in MEP computation - 2 stage RESP fit qwt=0.0005/0.001
Used in the Cornell et al., Kollman et al., Cheatham et al., Wang et al. & Hornak et al. AMBER force fields


  -2- RESP-B1
B3LYP/cc-pVTZ SCRF(IEFPCM,Solvent=Ether)//HF/6-31G** (1), (2) - Connolly surface algo. used in MEP computation - 2 stage RESP fit qwt=0.0005/0.001
Used in the Duan et al. AMBER force field
(Be sure to use the Gaussian 2003 program because the IEFPCM solvation model has changed in Gaussian 2009)


  -3- RESP-C1
HF/6-31G*//HF/6-31G* (1) - CHELPG algo. used in MEP computation - 2 stage RESP fit qwt=0.0005/0.001


  -4- RESP-O1
HF/6-31G*//HF/6-31G* (1) - Connolly surface algo. used in MEP computation - 2 stage RESP fit qwt=0.000184
Defined for OPLS force fields (4)


  -5- RESP-P1
HF/6-31G*//HF/6-31G* (1) - CHELPG algo. used in MEP computation - 2 stage RESP fit qwt=0.001184


  -6- RESP-A2
HF/6-31G*//HF/6-31G* (1) - Connolly surface algo. used in MEP computation - 1 stage RESP fit qwt=0.01


  -7- RESP-C2
HF/6-31G*//HF/6-31G* (1) - CHELPG algo. used in MEP computation - 1 stage RESP fit qwt=0.01
Used in the GLYCAM force fields


  -8- RESP-X1
b3lyp/6-31G*//b3lyp/6-31G* (1) - Connolly surface algo. used in MEP computation - 2 stage RESP fit qwt=0.0005/0.001


  -9- RESP-Y1
b3lyp/6-31G*//b3lyp/6-31G* (1) - CHELPG algo. used in MEP computation - 2 stage RESP fit qwt=0.0005/0.001


  -10- RESP-X2
b3lyp/6-31G*//b3lyp/6-31G* (1) - Connolly surface algo. used in MEP computation - 1 stage RESP fit qwt=0.01


  -11- RESP-Y2
b3lyp/6-31G*//b3lyp/6-31G* (1) - CHELPG algo. used in MEP computation - 1 stage RESP fit qwt=0.001


  -12- RESP-X11
b3lyp/6-31G*//b3lyp/6-31G* (1) - Connolly surface algo. used in MEP computation - 3 stage RESP fit qwt=0.0/0.0005/0.001


  -13- RESP-Y11
b3lyp/6-31G*//b3lyp/6-31G* (1) - CHELPG algo. used in MEP computation - 3 stage RESP fit qwt=0.0/0.0005/0.001


  -14- RESP-X22
b3lyp/6-31G*//b3lyp/6-31G* (1) - Connolly surface algo. used in MEP computation - 2 stage RESP fit qwt=0.0/0.01


  -15- RESP-Y22
b3lyp/6-31G*//b3lyp/6-31G* (1) - CHELPG algo. used in MEP computation - 2 stage RESP fit qwt=0.0/0.01


  -16- ESP-A1
HF/6-31G*//HF/6-31G* (1) - Connolly surface algo. used in MEP computation - 1 stage ESP fit qwt=0.0
Used in some AMBER, OPLS & CHARMM force field based simulations


  -17- ESP-C1
HF/6-31G*//HF/6-31G* (1) - CHELPG algo. used in MEP computation - 1 stage ESP fit qwt=0.0
Used in some OPLS & CHARMM force field based simulations


  -18- ESP-A2
HF/STO-3G//HF/STO-3G (3) - Connolly surface algo. used in MEP computation - 1 stage ESP fit qwt=0.0
Used in the old Weiner et al. AMBER force field.


  -19- ESP-C2
HF/STO-3G//HF/STO-3G (3) - CHELPG algo. used in MEP computation - 1 stage ESP fit qwt=0.0


  -20- ESP-X1
b3lyp/6-31G*//b3lyp/6-31G* (1) - Connolly surface algo. used in MEP computation - 1 stage ESP fit qwt=0.0


  -21- ESP-Y1
b3lyp/6-31G*//b3lyp/6-31G* (1) - CHELPG algo. used in MEP computation - 1 stage ESP fit qwt=0.0


  -22- DEBUG
For debugging purposes: do NOT select this keyword. The atomic charge values generated will be rotten!


- More generally, by using user-defined options in the System.config file an infinity of charge models can be obtained (see the 'METHOD_OPTCALC', 'BASSET_OPTCALC', 'METHOD_MEPCALC', 'BASSET_MEPCALC' and 'SURFMK_MEPCALC' keywords)...



  (1) Elements in white (H-Cl; atomic number Z=1 up to Z=17) and blue (K-Br; Z=19 up to Z=35) colors: the 6-31G* basis set is used in geometry optimization and MEP computation. Elements in green color (Rb-Lr; Z=37 up to Z=103): the Stuttgart/Dresden effective core potentials and associated basis sets available in the Gaussian program are used in geometry optimization and MEP computation (elements in yellow color are not handled by R.E.D. Server Development).
  (2) Originally developed with the SCRF/IEFPCM solvation model implemented in Gaussian 2003.
  (3) Useful only for compatibility with the past (Weiner et al. force field).
  (4) Henchman & Essex J.Comput.Chem. 1999, 20, 483-498.

Please, read the information related to the element radii implemented in R.E.D. Server Development as well.

Last update of this page: September 26th, 2022.

Université de Picardie Jules Verne. Sanford Burnham Prebys Medical Discovery Institute.
© 2009-2022. All rights reserved.

Valid XHTML 1.0 Strict CSS Valide !