Hints for 114-1 Exam Questions

Fundamental mid-term 

(1) Open 3D Atomistic Doc, Build Crystals, insert Atom one by one. Build -> Symmetry -> Find Sym. Then you cam Build > Sym > primitive cell

(2) See video

(3) box 12.00x12.01x12.02 

(4) calculate the Mulliken bond order of C-C bind in C2H2n, n=1,2,3. Then calculate that of a single C2 molecule, see how value fall in the typical data of C-C, C=C, or C-C to discuss the bond order.  

(5) note that O2 is paramagnetic (with spin=2) but N2 is non-magnetic. (If SCF of O2 is difficult to converge, try change from Density Mixing to All band EDFT.

Fundamental final

(1) Load Na and Cu from Structures Metal -> Pure-metals, convert them to primitive from. Set SCF k-point mesh to be very find by entring More-> k-points sub menu to change the separation to be roughly 0.01 (inverse angstromg or finner), after calculation finished, open the resulting model and choose analysis -> Fermi-sphere to show it in receprocal space. You will see Na is a simle sphere but Cu has holesw ith necks connecting each other.

(2) Load ZnO 

(3) Load Ni (fcc-Ni) and Fe (bcc), change then into premitive cells. Do spin-polarize calculations to the their magnetic moment per atom. Mordify elemnet so that Ni in bcc and Fe in fcc strictures, perform magnetic moment calculations for these new hypothetical crystals with cell optimization on. You will see

(4) see video

(5) see video

Application mid-term 

(1) Load diamnond structure from semiconductor ot ceramics, choose "Optical Properties" in "Properties" tab. after finish, 

(2) load graphite (no need to further change into signle-layered graphene), select one C atom in model and open core-hole to have core-hole in Modify - > Electronic Configurations menu. Request core-level spectroscopy in Properties list, and in SCF tick / untick core-role box spespectively to perform each calculation. After finished, select the same ion and analyze core-level spectra. For core-hole case a bigger supercell will be a better approximation than than a smaller one. To save time, resymmetrize cell with specific symmetry distiguish factor such as core level with hole will be good. 

(3) Draw CO2 in a box, (find symmetry is optional but will speed up calculation), choose Polarization, IR, Raman entry and 

after calculation finished, analyse IR in properties list and open Vibrational Analysis menu from Tools, click Calculate to calculate normal mode frequesncies. inspect one by one using Animation to see wing-flapping mode of O=C=O. 

(4) see video 

(5) load graphite crstal model from ceramics folder, Symmetry -> Make P1 to lift internal summetry and delete one layer. (optional) shift the remining layer to center, find symmetry to reduce the calculation time. Adjust a, b (a=b) of lattices so that they match the rate better the Si-Si distance in Si (compared with C-C distance in diamond), untick Metals method in Setip Tab nottherwide much longer calculation time, select Phonon dispersion in Phonon menu in the list of properties tab. untick the unnecessary LO-TO splitting to speed up calculations. Finally change pseudopotential to Norm-Conserving in Electronic Tab of the Calculation Menu. After job finished, Analyse IR to import Hassian then go to vibrational analysis to click calclate to get normal modes frequencies list, the one with "negative" value is is the one with imaginary frequency. Animate that mode to see the cause of instability of lattice deformation.

Application final

(1) see video

(2) cleave surface 111 of W bcc crystal to form a thick slab. 

(3) see video

(4) see video

(5) see video