# Open SourceMolecular Dynamics

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exercises:2014_ethz_mmm:basis_sets

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 exercises:2014_ethz_mmm:basis_sets [2014/03/25 16:19]sclelia [Part II: Estimate the binding energy of H2] exercises:2014_ethz_mmm:basis_sets [2014/10/15 12:37] (current)oschuett exercise:basis_sets renamed to exercise:2014_ethz_mmm:basis_sets Both sides previous revision Previous revision 2014/10/15 12:37 oschuett exercise:basis_sets renamed to exercise:2014_ethz_mmm:basis_sets2014/04/02 15:22 oschuett [Basis Sets] 2014/03/31 13:49 oschuett 2014/03/28 14:57 oschuett [1.Step] 2014/03/28 14:56 oschuett [Basis Sets] 2014/03/27 16:24 sclelia 2014/03/27 16:18 sclelia [1.Step] 2014/03/27 13:26 oschuett replace formular picture with latex version2014/03/26 15:25 sclelia [Part III: Questions] 2014/03/26 15:00 sclelia [1.Step] 2014/03/26 14:32 sclelia [2.Step] 2014/03/26 14:31 sclelia 2014/03/25 16:53 sclelia 2014/03/25 16:19 sclelia [Part II: Estimate the binding energy of H2] 2014/03/25 16:02 sclelia 2014/03/25 16:00 sclelia 2014/03/25 15:46 sclelia 2014/03/25 15:43 sclelia 2014/03/25 14:56 sclelia 2014/03/25 13:13 sclelia 2014/03/25 13:02 sclelia 2014/03/25 12:42 sclelia created Next revision Previous revision 2014/10/15 12:37 oschuett exercise:basis_sets renamed to exercise:2014_ethz_mmm:basis_sets2014/04/02 15:22 oschuett [Basis Sets] 2014/03/31 13:49 oschuett 2014/03/28 14:57 oschuett [1.Step] 2014/03/28 14:56 oschuett [Basis Sets] 2014/03/27 16:24 sclelia 2014/03/27 16:18 sclelia [1.Step] 2014/03/27 13:26 oschuett replace formular picture with latex version2014/03/26 15:25 sclelia [Part III: Questions] 2014/03/26 15:00 sclelia [1.Step] 2014/03/26 14:32 sclelia [2.Step] 2014/03/26 14:31 sclelia 2014/03/25 16:53 sclelia 2014/03/25 16:19 sclelia [Part II: Estimate the binding energy of H2] 2014/03/25 16:02 sclelia 2014/03/25 16:00 sclelia 2014/03/25 15:46 sclelia 2014/03/25 15:43 sclelia 2014/03/25 14:56 sclelia 2014/03/25 13:13 sclelia 2014/03/25 13:02 sclelia 2014/03/25 12:42 sclelia created Line 3: Line 3: In this exericse you will compare different basis sets and use them for computing the binding energy of an H2 molecule. In this exericse you will compare different basis sets and use them for computing the binding energy of an H2 molecule. - The cp2k basis set format is the following: + The cp2k basis set format is described in detail [[:basis_sets|here]]. - + - <​code>​ + - + - Nsets + - n1 lmin lmax Nexp Ncontr + - exp1 contr1 contr2 contr3 ​... + - exp2 contr4 contr5 contr6 ... + - Nexp.... + - n2 lmin lmax Nexp Ncontr + - exp1 contr1 contr2 contr3 ... + - exp2 contr4 contr5 contr6 ... + - Nexp.... + - ... + - ​ + - \\ + - Nsets = number of sets.  \\ + - n1,n2... = main quantum number (but it gets ignored by the program!) \\ + - lmin = min //l// (angular quantum number) of the set ( s = 0 ; p = 1 ; d = 2 ...) \\ + - lmax = max //l// (angular quantum number) of the set ( s = 0 ; p = 1 ; d = 2 ...) \\ + - Nexp = number of exponents of the set \\ + - Ncontr = number of contaction coefficients per angular quantum number \\ + - + - As an example: + - + - <​code>​ + - 2                 2 Sets + - 1 0 0 1 1         Set 1: lmin=0 ; lmax=0 (→ s functions!) ; 1 exponent ; 1 contraction + - 0.35 1          exponent1 of  set 1 ; contraction + - 1 1 1 1 1         Set 2: lmin=1 ; lmax=1 (→ p functions!) ; 1 exponenet ; 1 contraction + - 0.6 1           ​exponent1 of set 2 ;  contraction + - ​ + ===== Part I: Different basis sets for H and H2 ===== ===== Part I: Different basis sets for H and H2 ===== ==== 1.Step ==== ==== 1.Step ==== - Save the following input file. Comment lines are marked with ! + Run a calculation with the following input file. Comment lines are marked with ! Line 53: Line 21: ​ ​ &DFT &DFT - LSD                                      ! Requests a spin-polarized calculation for an odd number of electrons + LSD                                      ! Requests a spin-polarized calculation for non paired ​electrons MULTIPLICITY 2                           ! Multiplicity = 2S+1 (S= total spin momentum) MULTIPLICITY 2                           ! Multiplicity = 2S+1 (S= total spin momentum) &​POISSON ​                              ! Solver requested for non periodic calculations  ​ &​POISSON ​                              ! Solver requested for non periodic calculations  ​ PERIODIC NONE                        ​ PERIODIC NONE                        ​ - PSOLVER  ​MT                          ​! Type of solver + PSOLVER  ​WAVELET ​                    ! Type of solver &END POISSON &END POISSON &​QS ​                                   ! Parameters needed to set up the Quickstep framework &​QS ​                                   ! Parameters needed to set up the Quickstep framework Line 74: Line 42: ​ ​ &SUBSYS &SUBSYS + &​TOPOLOGY ​                             ! Section used to center the molecule in the simulation box. Useful for big molecules ​ + &​CENTER_COORDINATES ​                 ​ + &END + &END &CELL &CELL ABC 10.0 10.0 10.0 ABC 10.0 10.0 10.0 Line 90: Line 62: &​END &​END ​POTENTIAL ALL                         ! Specifes that the potential is for all electron calculations. ​POTENTIAL ALL                         ! Specifes that the potential is for all electron calculations. - &​POTENTIAL ​                           ! Usual all eletcron ​potential for H + &​POTENTIAL ​                           ! Usual all electron ​potential for H ​1 ​   0    0 ​1 ​   0    0 ​0.20000000 ​   0 ​0.20000000 ​   0 Line 121: Line 93: <​code>​ <​code>​ H 0 0 0 H 0 0 0 - H 0.8 0 0 + H 0.75 0 0 ​ - ​ The H2 molecule ​has an even number of electrons. Remember to take out the LSD and MULTIPLICITY keywords. ​ + ​ The H2 molecule ​does not have unpaired ​electrons. Remember to take out the LSD and MULTIPLICITY keywords. ​ ===== Part II: Estimate the binding energy of H2 ===== ===== Part II: Estimate the binding energy of H2 ===== Binding energy: \\ Binding energy: \\ - {{ :​exercise:​ppp.jpg?​300 |}} + $\sum E_\text{products} - \sum E_\text{rectants} = E(H_2) - 2 \cdot E(H)$ ​ The binding energy value is significant only if the same basis is used for both reactants and products. ​ The binding energy value is significant only if the same basis is used for both reactants and products. ​ Line 149: Line 121: ===== Part III: Questions ===== ===== Part III: Questions ===== - 1.1- Report two self-made basis sets and the corresponding H energy. + - What is the effect of:\\ - + - 1.2- What is the effect of:\\ + * increasing/​decreasing the value of the exponents for the given basis? * increasing/​decreasing the value of the exponents for the given basis? * adding sets with p,d symmetry to the basis? You have the same effect in H and H2? * adding sets with p,d symmetry to the basis? You have the same effect in H and H2?