exercises:2014_ethz_mmm:basis_sets
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exercise:basis_sets [2014/03/25 15:46] – sclelia | exercise:2014_ethz_mmm:basis_sets [2014/10/15 12:37] – exercise:basis_sets renamed to exercise:2014_ethz_mmm:basis_sets oschuett | ||
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====== Basis Sets ====== | ====== Basis Sets ====== | ||
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]]. |
- | + | ||
- | < | + | |
- | + | ||
- | 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: | + | |
- | + | ||
- | < | + | |
- | 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 | + | |
- | </ | + | |
===== 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 ! |
<code - mybasis.inp > | <code - mybasis.inp > | ||
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| | ||
&DFT | &DFT | ||
- | LSD ! Requests a spin-polarized calculation for an odd number of electrons | + | LSD ! Requests a spin-polarized calculation for non paired |
MULTIPLICITY 2 ! Multiplicity = 2S+1 (S= total spin momentum) | MULTIPLICITY 2 ! Multiplicity = 2S+1 (S= total spin momentum) | ||
& | & | ||
PERIODIC NONE | PERIODIC NONE | ||
- | PSOLVER | + | PSOLVER |
&END POISSON | &END POISSON | ||
& | & | ||
Line 73: | Line 42: | ||
| | ||
&SUBSYS | &SUBSYS | ||
+ | & | ||
+ | & | ||
+ | &END | ||
+ | &END | ||
&CELL | &CELL | ||
ABC 10.0 10.0 10.0 | ABC 10.0 10.0 10.0 | ||
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& | & | ||
| | ||
- | & | + | & |
| | ||
| | ||
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==== 2.Step ==== | ==== 2.Step ==== | ||
Try to change the basis set, and report the obtained energy values for H. | Try to change the basis set, and report the obtained energy values for H. | ||
- | After a couple of tries on your own, try to use some of the literature basis sets (reported | + | After a couple of tries on your own, try to use some of the literature basis sets (given at the end of this exercise). |
At the end, you should get a table like this : | At the end, you should get a table like this : | ||
- | ^ Basis set ^ Energy | + | ^ Basis set ^ Energy |
| mybasis (from given input) | | mybasis (from given input) | ||
| basis try 1 | .... | | | basis try 1 | .... | | ||
Line 113: | Line 86: | ||
| pc-1 | .... | | | pc-1 | .... | | ||
| pc-2 | .... | | | pc-2 | .... | | ||
- | | .... | .... | | ||
<note tip>Is always good to keep record of self-created basis sets, to track the effect of a change in value and number of exponents, contractions....etc.. </ | <note tip>Is always good to keep record of self-created basis sets, to track the effect of a change in value and number of exponents, contractions....etc.. </ | ||
Line 121: | Line 93: | ||
< | < | ||
H 0 0 0 | H 0 0 0 | ||
- | H 0.8 0 0 | + | H 0.75 0 0 |
</ | </ | ||
- | <note important> | + | <note important> |
===== Part II: Estimate the binding energy of H2 ===== | ===== Part II: Estimate the binding energy of H2 ===== | ||
- | Binding energy: | ||
- | < math format > | ||
- | < /math > | ||
+ | Binding energy: \\ | ||
+ | \[ \sum E_\text{products} - \sum E_\text{rectants} = E(H_2) - 2 \cdot E(H) \] | ||
+ | <note important> | ||
+ | |||
+ | |||
+ | You can now update your table: | ||
+ | |||
+ | ^ Basis set ^ Energy | ||
+ | | mybasis (from given input) | ||
+ | | basis try 1 | .... | .... | .... | | ||
+ | | basis try 2 | .... | .... | .... | | ||
+ | | .... | .... | .... | .... | | ||
+ | | pc-0 | .... | .... | .... | | ||
+ | | pc-1 | .... | .... | .... | | ||
+ | | pc-2 | .... | .... | .... | | ||
+ | | .... | .... | .... | .... | | ||
===== Part III: Questions ===== | ===== Part III: Questions ===== | ||
- | What is the effect of:\\ | + | - What is the effect of:\\ |
* increasing/ | * increasing/ | ||
* 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? | ||
+ | |||
+ | |||
+ | ===== Part IV: Additional basis sets ===== | ||
+ | |||
+ | |||
+ | |||
+ | H pc-0 | ||
+ | 2 | ||
+ | 1 0 0 2 1 | ||
+ | 4.34480000 | ||
+ | 0.66049000 | ||
+ | 1 0 0 1 1 | ||
+ | 0.13669000 | ||
+ | |||
+ | H pc-1 | ||
+ | 3 | ||
+ | 1 0 0 3 1 | ||
+ | | ||
+ | 1.86870000 | ||
+ | 0.41821000 | ||
+ | 1 0 0 1 1 | ||
+ | 0.10610000 | ||
+ | 1 1 1 1 1 | ||
+ | 1.00000000 | ||
+ | |||
+ | H pc-2 | ||
+ | 6 | ||
+ | 1 0 0 4 1 | ||
+ | | ||
+ | | ||
+ | 2.59930000 | ||
+ | 0.73513000 | ||
+ | 1 0 0 1 1 | ||
+ | 0.23167000 | ||
+ | 1 0 0 1 1 | ||
+ | 0.07414700 | ||
+ | 1 1 1 1 1 | ||
+ | 1.60000000 | ||
+ | 1 1 1 1 1 | ||
+ | 0.45000000 | ||
+ | 1 2 2 1 1 | ||
+ | 1.25000000 | ||
+ | |||
+ | |||
+ | |||
+ | |||
exercises/2014_ethz_mmm/basis_sets.txt · Last modified: 2020/08/21 10:15 by 127.0.0.1