exercises:2014_ethz_mmm:mo_ethene
no way to compare when less than two revisions
Differences
This shows you the differences between two versions of the page.
Previous revisionLast revision | |||
— | exercise:2014_ethz_mmm:mo_ethene [2014/10/15 13:38] – oschuett | ||
---|---|---|---|
Line 1: | Line 1: | ||
+ | ====== Molecular orbitals of Ethene ====== | ||
+ | In this exercise, you will perform an electronic structure calculation to obtain the ethene molecular orbitals (MOs). If performed correctly, your calculations will produce a list of occupied and non occupied MOs and a series of *.cube files, that allow the visualization of the oribital with VMD. | ||
+ | |||
+ | ==== 1. Step ==== | ||
+ | Run a calculation with the following (commented) input file. \\ | ||
+ | Note that the file contains explicit basis sets and potential for all-electron calculations. An explanation of the basis set formats is given here: [[basis_sets|Basis Sets]] | ||
+ | |||
+ | <code - ethene.inp > | ||
+ | |||
+ | |||
+ | &GLOBAL | ||
+ | PROJECT ethene | ||
+ | RUN_TYPE ENERGY | ||
+ | PRINT_LEVEL MEDIUM | ||
+ | &END GLOBAL | ||
+ | |||
+ | & | ||
+ | METHOD Quickstep | ||
+ | &DFT | ||
+ | |||
+ | & | ||
+ | NHOMO 5 ! Number of HOMOs to be printed (count starts from the highest occupied orbital. -1 = all). Here 5. | ||
+ | NLUMO 5 ! Number of LUMOs to be printed (count starts from the lowest unoccupied orbital). Here 5. | ||
+ | &END MO_CUBES | ||
+ | &END PRINT | ||
+ | & | ||
+ | PERIODIC NONE | ||
+ | PSOLVER | ||
+ | &END POISSON | ||
+ | & | ||
+ | METHOD GAPW ! Method: gaussian and augmented plane waves | ||
+ | &END QS | ||
+ | |||
+ | & | ||
+ | MAX_ITER_LUMOS 10000 | ||
+ | EPS_SCF 1.0E-6 | ||
+ | SCF_GUESS ATOMIC | ||
+ | MAX_SCF 60 | ||
+ | EPS_LUMOS | ||
+ | & | ||
+ | EPS_SCF 1.0E-6 | ||
+ | MAX_SCF 6 | ||
+ | &END | ||
+ | &END SCF | ||
+ | |||
+ | & | ||
+ | & | ||
+ | &END XC_FUNCTIONAL | ||
+ | & | ||
+ | & | ||
+ | EPS_SCHWARZ 1.0E-10 | ||
+ | &END SCREENING | ||
+ | &END HF | ||
+ | &END XC | ||
+ | &END DFT | ||
+ | |||
+ | &SUBSYS | ||
+ | &CELL | ||
+ | ABC 10 10 10 | ||
+ | PERIODIC NONE ! Non periodic calculations. That's why the POISSON scetion is needed | ||
+ | &END CELL | ||
+ | & | ||
+ | & | ||
+ | &END | ||
+ | &END | ||
+ | &COORD | ||
+ | C | ||
+ | C | ||
+ | H | ||
+ | H | ||
+ | H | ||
+ | H | ||
+ | &END COORD | ||
+ | &KIND H ! Basis set and potential for H | ||
+ | & | ||
+ | 2 | ||
+ | 1 0 0 3 1 | ||
+ | | ||
+ | 2.82539370 | ||
+ | 0.64012170 | ||
+ | 1 0 0 1 1 | ||
+ | 0.16127780 | ||
+ | & | ||
+ | | ||
+ | & | ||
+ | | ||
+ | | ||
+ | & | ||
+ | &END KIND | ||
+ | &KIND C ! Basis set and potential for C | ||
+ | & | ||
+ | 4 | ||
+ | 1 0 0 6 1 | ||
+ | | ||
+ | 457.36951000 | ||
+ | 103.94869000 | ||
+ | | ||
+ | 9.28666300 | ||
+ | 3.16392700 | ||
+ | 1 0 1 3 1 1 | ||
+ | 7.86827240 | ||
+ | 1.88128850 | ||
+ | 0.54424930 | ||
+ | 1 0 1 1 1 1 | ||
+ | 0.16871440 | ||
+ | 1 2 2 1 1 | ||
+ | 0.80000000 | ||
+ | & | ||
+ | | ||
+ | & | ||
+ | | ||
+ | | ||
+ | & | ||
+ | &END KIND | ||
+ | &END SUBSYS | ||
+ | &END FORCE_EVAL | ||
+ | |||
+ | </ | ||
+ | |||
+ | |||
+ | ==== 2. Step ==== | ||
+ | |||
+ | If the calculation was performed correctly, a list of ALL the occupied MOs and 3 (as specified in the input) unoccupied MOs eigenvalues are printed in the output. \\ | ||
+ | The ethene band gap (energy difference between HOMO and LUMO) is also printed. | ||
+ | < | ||
+ | |||
+ | **** **** ****** | ||
+ | ***** ** *** *** ** | ||
+ | | ||
+ | ***** ** ** ** ** | ||
+ | **** ** ******* | ||
+ | |||
+ | ..... | ||
+ | Eigenvalues of the occupied subspace spin 1 | ||
+ | | ||
+ | list of eigenvalues | ||
+ | .... | ||
+ | |||
+ | Lowest Eigenvalues of the unoccupied subspace spin 1 | ||
+ | | ||
+ | list of eigenvalues | ||
+ | ..... | ||
+ | |||
+ | HOMO - LUMO gap [eV] : | ||
+ | ...... | ||
+ | |||
+ | |||
+ | **** **** ****** | ||
+ | ***** ** *** *** ** | ||
+ | | ||
+ | ***** ** ** ** ** | ||
+ | **** ** ******* | ||
+ | |||
+ | </ | ||
+ | |||
+ | <note important> | ||
+ | |||
+ | |||
+ | ==== 3. Step ==== | ||
+ | |||
+ | In addition to the list of eigenvalues ( printed directly in the output file) a series of *.cube files is generated. \\ | ||
+ | The number of cubes strictly depends on what you have specified in the PRINT_MO section. No extra files are generated (while in the output a default list of all the occupied MOs eigenvalues is anyway produced.) | ||
+ | ∗.cube files report the structure of a given MO and can be visualized with VMD: | ||
+ | |||
+ | * To run vmd: vmd ethene-WFN_00008_1-1_0.cube | ||
+ | * To visualize the molecule (sometimes the default settings are not visible with VMD in Brutus): | ||
+ | * To visualize the MO structure in VMD: | ||
+ | * In Isosurfaces, | ||
+ | * In Isosurfaces, | ||
+ | * To visualize the positive and the negative part of an orbital simultaneously, | ||
+ | * To give the two representations different colors, set their " | ||
+ | |||
+ | What you get should look similar to this: | ||
+ | {{ ethene_pi_orbital.png |}} | ||
+ | ==== Questions ==== | ||
+ | |||
+ | - Quickly sketch the energy distribution for the occupied MOs and the five unoccupied MOs. \\ | ||
+ | - By using VMD, identify the shape and energy of the π and π* orbitals. | ||
+ | |||
+ | |||
+ | | ||
exercises/2014_ethz_mmm/mo_ethene.txt · Last modified: 2020/08/21 10:15 by 127.0.0.1