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quickstart [2025/10/13 13:23] – [Simple input] wernerquickstart [2025/10/14 08:54] (current) – [Simple input] werner
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 ''run DF-KS,b3lyp geometry=h2o.xyz basis=avtz'' ''run DF-KS,b3lyp geometry=h2o.xyz basis=avtz''
  
-where avtz is a short name for the aug-cc-pVTZ basis. The prefix DF- turns on density fitting approximations for the integrals, which is strongly recommended for efficiency, in particular for larger molecules.+where avtz is a short name for the aug-cc-pVTZ basis, and 
 +the geometry is provided in an external file holding the x,y,z coordinates in Angstrom. Alternatively, the geometry can be given as z-matrix in curley brackets.  
 + 
 +The prefix DF- turns on density fitting approximations for the integrals, which is strongly recommended for efficiency, in particular for larger molecules.
  
 A most simple example for a CCSD(T) input is: A most simple example for a CCSD(T) input is:
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 ''run CCSD(T) geometry=h2o.xyz basis=avtz'' ''run CCSD(T) geometry=h2o.xyz basis=avtz''
  
-where the geometry is provided in an external file holding the x,y,z coordinates in Angstrom. Alternatively, the geometry can be given as z-matrix in curley brackets.  
  
 The entries can come in any order, for example The entries can come in any order, for example
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 ''run basis=avtz method=CCSD(T) geometry=h2o.xyz ''  ''run basis=avtz method=CCSD(T) geometry=h2o.xyz '' 
  
-would work as well. The key "method=" is optional. Entries on the "run" command must be separated by blank or semicolon (;) (but semicolon cannot follow ''run''). Some commands or directives can have options, which are separated by commas. Blanks before and after commas, semicolons, or equal signs ($=$) are ignored. Input can be given in upper or lower or mixed case.+works as well. The key "method=" is optional. Entries on the "run" command must be separated by blank or semicolon (;) (but semicolon cannot follow ''run''). Some commands or directives can have options, which are separated by commas. Blanks before and after commas, semicolons, or equal signs ($=$) are ignored. Input can be given in upper or lower or mixed case.
  
 The run command line can optionally be split to two or multiple lines between the entries that are separated by blank or semicolon. In this case the whole block must be embraced by curley brackets, e.g. The run command line can optionally be split to two or multiple lines between the entries that are separated by blank or semicolon. In this case the whole block must be embraced by curley brackets, e.g.
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 pno-lmp2     !local pno-lmp2 pno-lmp2     !local pno-lmp2
 pno-lccsd    !local coupled cluster with singles and doubles pno-lccsd    !local coupled cluster with singles and doubles
-pno-lccsd(t) !local coupled cluster with singles and doubles+pno-lccsd(t) !local coupled cluster with singles, doubles, and perturbative triples
 multi        !mcscf/casscf multi        !mcscf/casscf
 casscf       !same as multi casscf       !same as multi
-mrci         !internally contracted multi-reference CI+mrci         !multi-reference CI with internally contracted doubles 
 +mrcic        !multi-reference CI with internally contracted singles and doubles
 caspt2       !caspt2 caspt2       !caspt2
 nevpt2       !n-electron valence perturbation theory nevpt2       !n-electron valence perturbation theory
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 </code> </code>
  
-All higher order methods contain the lower-level ones. For example, ccsd(t) contains HF, MP2, and CCSD. +All higher order methods contain the lower-level ones. For example, ccsd(t) contains HF, MP2, and CCSD, and MRCI contains CASPT2. 
  
-For larger molecules, it is advisable to use density fitted methods. The following ones are efficiently implemented: +''For larger molecules, it is advisable to use density fitted methods (activated by the prefix DF-).'' Note that in some other programs this is denoted RI-approximation, but in Molpro RI refers to resolution of the identity approximations of the many-electron integrals in F12 methods. This is distinct from DF-approximations of standard 2-electron Coulomb integrals.  
 + 
 +The following ones are efficiently implemented: 
  
  <code>  <code>
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 PNO methods are density fitted in any case.  PNO methods are density fitted in any case. 
  
-For all listed correlation methods, explicitly correlated versions are available by appending -f12 to the command [e.g. ccsd(t)-f12, or pro-lccsd(t)-f12]. The use of F12 methods is strongly recommended since the basis set error is much reduced. Appropriate basis set for such calculations are avtz or avtz-f12.+For most listed correlation methods, explicitly correlated versions are available by appending -F12 to the command [e.g. ccsd(t)-f12, or pno-lccsd(t)-f12]. ''The use of F12 methods is strongly recommended since the basis set error is much reduced.'' Appropriate basis sets for such calculations are avtz or avtz-f12. F12 is not available for MRCIC and NEVPT2.
  
-method, geometry, and basis set are compulsory for running a calculation. By default, only an energy calculation is done. However, other calculation types can be requested by specifying one of the following directives (the parts in bracket can be omitted):+Method, geometry, and basis set are compulsory for running a calculation. By default, only a single energy calculation is done. However, other calculation types can be requested by specifying one of the following directives (the parts in brackets can be omitted or are optional):
  
  <code>  <code>
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 freq[quencies]                   !optimize the geometry and compute the harmonic vibrational frequencies (wavenumber). freq[quencies]                   !optimize the geometry and compute the harmonic vibrational frequencies (wavenumber).
 extrapolate,basis=basis1:basis2  !carry out a basis set extrapolation using basis1 and basis2. extrapolate,basis=basis1:basis2  !carry out a basis set extrapolation using basis1 and basis2.
-interact                         !automatically compute CP-corrected interaction energies for a dimer.+interact[,do_nocp]               !automatically compute CP-corrected interaction energies for a dimer.  
 +                                 !If do_nocp is given, the CP-uncorrected values are computed as well.
 </code> </code>
  
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 ''run caspt2 geometry=h2o.xyz basis=avtz'' ''run caspt2 geometry=h2o.xyz basis=avtz''
  
 +6.) TDDFT excitation energies:
 +
 +''run df-tddft,states=[4.1,4.2,4.3,4.4] functional=b3lyp basis=avtz geometry=h2o.xyz''
 +
 +This computes 4 excited states for each of the four IRREPS of C2v.
 +
 +7.) CC2 excitation energies:
 +
 +''run df-cc2,states=[4.1,4.2,4.3,4.4] basis=avtz geometry=h2o.xyz''
 +
 +This computes the ground state and 4 excited states for each of the four IRREPS of C2v.
 +
 +8.)CASSCF calculation using state-averaging over three state symmetries:
 +
 +''run casscf wfsym=[2,3,1] spin=1 geometry={O;H,O,1.83}''
 +
 +This carries out a state-averaged CASSCF calculation for symmetries 2,3,1 ($^2\Pi_x$,$^2\Pi_y$, and $^2\Sigma^+$).
 +
 +9. )MRCI calculation using state-averaged CASSCF reference functions:
 +
 +''run mrci wfsym=[2,3,1] spin=1 geometry={O;H,O,1.83}''
 +
 +In this case first a state-averaged CASSCF calculation for symmetries 2,3,1 ($^2\Pi_x$,$^2\Pi_y$,  and $^2\Sigma^+$) is carried out. Subsequently an MRCI calculation is done for each state symmetry separately.
 +
 +
 +10.) Several run command lines can follow each other. For example, compute the lowest ionisation potential of H2O using MRCI:
 +
 +<code>
 +run mrci basis=vtz geometry=h2o.xyz  !casscf/mrci for neutral ground state
 +eci=energy                           !save mrci energy in variable eci
 +eda=energd                           !save mrci+q (Davidson corrected) energy in variable eda
 +run mrci charge=1 wfsym=3 spin=1     !calculation for 2B2 state
 +ipci=(energy-eci)*toev               !compute mrci ionization potential in ev  
 +ipda=(energd-eda)*toev               !compute mrci+q ionization potential in ev
 +</code>
 +
 +11.) It is also possible to combine the run command with other standard molpro input, for example:
 +
 +<code>
 +geometry={O;                 !Z-matrix for water
 +          H1,O,R;
 +          H2,O,R,H1,THETA}
 +basis=vtz                    !use VTZ basis
 +R=0.96 Ang                   !start bond distance
 +Theta=104                    !start bond angle
 +
 +run mp2 optg                 !optimize MP2 energy
 +mp4                          !do single-point MP4 at MP2 geometry
 +ccsd(t)                      !do single-point CCSD(T) at MP2 geometry
 +</code>
 The following sections give more basic information about carrying electronic structure calculations with Molpro. The following sections give more basic information about carrying electronic structure calculations with Molpro.