Chapter 6. Calculation of physical and chemical properties of nanomaterials. (2 hours).

1. Chapter 1. Introduction, perspectives, and aims. On the science of simulation and modelling. Modelling at bulk, meso, and nano scale. (2 hours). Chapter 2. Experimental Techniques in Nanotechnology. Theory and Experiment: “Two faces of the same coin” (2 hours). Chapter 3. Introduction to Methods of the Classic and Quantum Mechanics. Force Fields, Semiempirical, Plane-Wave pseudpotential calculations. (2 hours) Chapter 4. Introduction to Methods and Techniques of Quantum Chemistry, Ab initio methods, and Methods based on Density Functional Theory (DFT). (4 hours) Chapter 5. Visualization codes, algorithms and programs. GAUSSIAN; CRYSTAL, and VASP. (6 hours)

2. . Chapter 6. Calculation of physical and chemical properties of nanomaterials. (2 hours). Chapter 7. Calculation of optical properties. Photoluminescence. (3 hours). Chapter 8. Modelization of the growth mechanism of nanomaterials. Surface Energy and Wullf architecture (3 hours) Chapter 9. Heterostructures Modeling. Simple and complex metal oxides. (2 hours) Chapter 10. Modelization of chemical reaction at surfaces. Heterogeneous catalysis. Towards an undertanding of the Nanocatalysis. (4 hours)

3. Chapter 6. Calculation of physical and chemical properties of nanomaterials Lourdes Gracia y Juan Andrés Departamento de Química-Física y Analítica Universitat Jaume I Spain & CMDCM, Sao Carlos Brazil Sao Carlos, Novembro 2010

4. Applications in front-line research - High-pressure phase transitions in crystalline systems - Li Diffusion in Crystalline Systems - Two State Reactivity and heterogeneous catalysis

5. Structrural properties of ceramic materials. Substitution and doping processes. • Electronic and optical properties of piezoelectric and catalytic materials. • Adsorption processes on metal oxide surfaces. Computational and Theoretical Chemistry (CTC) Solid State Chemistry

6. Cooperation Experimental work CTC • Prediction • Interpretation • Characterization of chemical species of difficult experimental detection

7. crystalline structures • Compressibility • (polyhedra, bonds) • - polymorphism PESs of different spin multiplicities • stationary points • reaction paths • crossing points Atoms (C, Li) in metals and metal oxides • reaction paths • activation barriers High Pressure Effects Chemical Reactivity Diffusion Processes

8. Pressure effect • Methodology: • Density Functional Theory (DFT) • Periodic Models • Programs: CRYSTAL, VASP • Properties : • - Geometry optimization, macroscopic parameters: • equations of state, B0 , e , n • - Electronic properties: r , DOS, band structure, dEg/dP • - Theoric vibrational spectra (Raman , IR), vibrational modes asignation, w, dw/dP. • Characterization of phase transition mechanisms

9. Optimización de la geometría Curva ET-V código GIBBS: Ecuación de Estado POLYHEDRA ANALYSIS V0, B0 , B0’ L. Gracia, A. Beltrán, J. Andrés, R. Franco and J. M. Recio Pressure effect Physical Review B66, 224114 (2002) • MgAl2O4 METHODOLOGY CRYSTAL Program DFT (B3LYP) 8-511G*- Mg, Al 8-411G* -O

10. Occuped tetraheda MgO4 Occuped octahedra AlO6 Unfilled tetrahedra (O4)1 y (O4)2 Unfilled octahedra O6

11. 150 100 50 tipo-titanita MgO+a-Al2O3 tipo-ferrita G (kJ/mol) 0 cubica -50 0 10 20 30 40 50 60  distancia Mg2+-O2- P(GPa)  empaquetamiento COMPRESIBILIDADES LINEALES Al-O/Mg-O cúbica ortorrómbicas MgO y -Al2O3 IC (Mg2+) 4 6 8 ESTABILIDAD GLOBAL MgO y -Al2O3 cúbica titanita ferrita

12. B0 (GPa) CdGa2Se4 CdCr2Se4 Exp 101 48 92 (no magnetic) Teor 44 80 (ferromagnetic) A. Waskowska. L. Gerward, J. Staun Olsen, M. Feliz, R. Llusar, L. Gracia, M. Marqués and J. M. Recio Journal of Physics: Condensed Matter16, 53-63 (2004). • CdGa2Se4, CdCr2Se4 POLYHEDRA ANALYSIS Cd2+ tetrahedra Cr3+ octahedra Cúbic Fd3m Tetragonal I4

13. L. Gracia, M. Marqués, A. Beltrán, A. Martín Pendás, and J. M. Recio J. Physics: Condensed Matter 16, s1263 (2004) • Polymorphs of CO2 METHODOLOGY Programa VASP PAW (LDA) Análisis topológico (AIM) ESTRUCTURES CO2-III Cmca CO2-I Pa3

14. Pa3Cmca(1) Cmca(2) P212121 I42dP42/mnm 36.87 36.97 37.05 22.95 22.28 17.44 16.6 15.0 16.9 133.6 142.7 327.2 1.168(2)1.168(2) 1.265(2) 1.385(4) 1.385(4) 1.577(4) 1.679(2) V0(Å3) B0(GPa) dC-O (Å) P42/mnm CO2-V CO2-V P212121 CO2-V I42d Molecular to polymeric phase transition: CO2

15. (r) = 0  /2 > 0 polar C=O con CO2-I y CO2-III (1)  /2 <0 covalente C-O con CO2-V Isocontornos de la laplaciana de CO2-III (2): Configuration T TEORÍA DE ATOMOS EN MOLECULAS (AIM) Punto crítico firma sentido químico máximo -3 nucleos Punto de silla -1 enlaces -  /2 carácter y fuerza del enlace

16. A. Beltrán, L. Gracia and J. Andrés TiO2 polymorphs J. Phys. Chem. B 110, 23417 (2006) anatase → brookite at 3.8 GPa rutile → brookite at 6.2 GPa.

17. Ti4c Ti5c [100] [010] [010] [100] [001] [001] Ti5c [110] [110] [001] Brookite Surfaces (100) stabilities (010) < (110) < (100) the electronic structure: - direct band gap in all of them - minimum gap energy: (110) (010) (110)

18. A. Beltrán, L. Gracia and J. Andrés Journal of Physical Chemistry B 111, 6479-6485 (2007). SnO2 polymorphs Highest bulk moduli values of 293 (pyrite) and 322 GPa (fluorite) phases

19. SnO2 polymorphs The phase transition sequence is consistent with an increase of coordination number of the tin ions, from 6 in the first three phases to 6+2 in the pyrite phase, 7 in the ZrO2-type orthorhombic phase I, 8 in fluorite phase and 9 in cotunnite orthorhombic phase II.

20. enthalpy vs presión curve (CrVO4-type as reference) • Vt= [V2(Pt)-V1(Pt)] / V1(Pt) • 0.8 GPa → volume change of 11.8%. • 3.8 GPa → volume reduction of 8.5%. L. Gracia, A. Beltrán and D. Errandonea Phys. Rev. B 80, 094105 (2009) TiSiO4 a) CrVO4,-type b) zircon c)scheelite B3LYP calculations (CRYSTAL06 program)

21. In scheelite the low frequency mode with g< 0 , T(Bg), suggest the possibility of a transition to the post-scheelite structure, fergusonite or wolframite

22. D. Errandonea, R. S. Kumar, L. Gracia, A. Beltrán, S. N. Achary, and A. K. Tyagi Physical Review B 80, 094101 (2009) ThGeO4 fergusonite scheelite zircon PBE calculations (VASP program)

23. Computations: Zircon as the most stable to 2 GPa Scheelite P > 2 GPa Fergusonite (post-scheelite) at 31 Gpa XRD: Zircon  Scheelite  Fergusonite 11 GPa 26GPa Decompression fergusonite – scheelite: no histeresis zircon-scheelita: not reversible.

24. Bastide diagram for ABX4 structures Dashed lines: evolution of the ionic radii ratio with pressure D. Errandonea, F.J. Manjón , Progress in Materials Science, 53, 711 (2008)

25. c a b CaSO4 Monazite Anhydrite Scheelite Barite 1.955 1.958

26.  AgMnO4 Scheelita Barita Monazita Anhidrita H-P curve E-V curve anhydrite → monazite at Pt 5 GPa , reduction of volum -2% at 5GPa monazite → barite (and/or scheelite) at 8 GPa

27. SiO2 polymorphs -cristobalite is 0.1 eV more stable than stishovite at P=0 transition as low as 0.5 GPa with a large volume collapse a-cristobalite stihovite L. Gracia, J. Contreras-García, A. Beltrán and J. M. Recio High Press Res29, 93-96 (2009).

28. SiO2 polymorphs The atomic displacements connecting both polymorphs can be described under a martensitic approach (collective and concerted movements of all the atoms) in terms of a transition path of P41212 symmetry. The transition path is traced up using a normalized coordinate: x, that evolves continuously from 0 (-cristobalite, c) to 1 (stishovite, s)

29. Experimental Study DAC  Diamond Anvil Cell Sincrotrones ALBA Nuevos Beamlines dedicados a altas presiones (APS/ESRF/SPring8/Diamond/Soleil/ALBA) Electrones acelerados a una energía de 7 mil millones de electron-volts (7 GeV). Radiación sincrotrón: radiación electromagnética producida por partículas cargadas que se mueven a alta velocidad (una fracción apreciable de la velocidad de la luz) en un campo magnético. Ionización del aire producida por un haz de rayos X en un sincrotrón

30. Impurities in metals Alteration • Structure • Cleveage of adsorbates • Catalysis METHODOLOGY VASP Program Plane waves / GGA • Diffusion Procesess

31. tet1 oct1 tet2 tet1 oct2 Oct > Tet1 > Tet2 DE(relative,eV):0.00>0.41>0.52 • Stability of C in Pd(111) - subsurface interstices R30º Unit cell L. Gracia, M. Calatayud, J. Andrés, C. Minot and M. Salmeron Physical Review B71, 033407-1(-4) (2005).

32. -0.92 1.9 1.9 DE (eV) 2.4 -0.75 -0.17 -0.74 ts2 -0.13 1.9 tet1 ts1 tet2 0.86 2.8 0.74 oct1 oct2 tet2 0.52 7 11 9 tet1 0.41 -0.35 2.0 10 -0.53 -0.15 2.0 oct 1.90 oct 0.0 y 0.34 0.36 0.32 0.38 0.40 0.42 0.50 0.44 0.46 0.48 Horizontal Diffusion

33. oct1 tet2 7 DE (eV) ts1 ts2 tet1 oct2 1.93 1.80 1.14 tet1 tet2 0.63 0.63 0.27 0.0 oct2 oct1 0.4 0.6 0.8 1 1.5 3 3.5 2 y 2.5 z To bulk Diffusion

34. L. Gracia, J. García Cañadas, G. García-Belmonte, A. Beltrán, J. Andrés and J. Bisquert distortion d(O1-O2) Minimum energy path 2.65 Å without Li - 4.25 Å 4 O, 2 W Maximum energy barrier d(Li-O)= d(Li-W)=2.09 Å Electrochemical and Solid State Letters. 8, J21 (2005) • Li in WO3 Cell 2x2 Pm3m

35. Energy barrier variation with x (●) experimental data of DJ. (○) theoretical calculations relation with c=1.55 (simulation) and 1.25 (experiment). Rect lines Process more favorable for low doped systems

36. Intercalation and diffusion of Li: Li1+xTi2O4 (spinel ) Li diffusion processes from tetrahedral 8a sites to ctahedral 16c sites are thermodynamically favorable only in the compositions x > 0.250. M. Anicete-Santos, L. Gracia, A. Beltrán and J. Andrés Phys Rev. B77, 085112 (2008)

37. Intercalation and diffusion of Li: Li1+xTi2O4 (spinel ) M. Anicete-Santos, L. Gracia, A. Beltrán and J. Andrés Phys Rev. B77, 085112 (2008)

38. METHODOLOGY PC TS’ TS TS TS’ TS PC TS’ PC Program GAUSSIAN DFT (B3LYP) 6-311G(2d,p) PC R’ • Vibrational Analysis • IRC R’ R’ P’ P P R R P’ P’ P R • IRCs by Yoshizawa et al. TS closer IRC minimum Single-point energy calculation with the other spin electronic state geometries • MECP by Harvey et al. ortogonal to CP Ei d Ei y d q Gradients Parallel to SEPs • Chemical Reactivity

39. VO+ + CHOCH3 + C2H4 VO+ + H2O + C2H4 + C2H6 VO2+ V(OH)2+ + C2H4 V(OH)2+ + C3H4 C3H6 + VO+ + CO(CH3)2 / CHOC2H5 • Reaction mechanisms • Spin inversion processes crossing points • Topological analysis of electron density NbO3- + H2O + O2 NbO5- + H2O MO(H2O)+ M(OH)2+ M=(V, Nb, Ta)

40. L. Gracia, J. R. Sambrano, V. S. Safont, M. Calatayud, A, Beltrán and J. Andrés VO2+ + C2H4 VO+ + CHOCH3 D G (kcal/mol) Mecanismo 1 Mecanismo 2 40 + + 20 t-VO + s-CHOCH t-VO + s-CHOCH 3 3 CP2 + s-VO + s-C H s-TS4/5 s-TS5/3 s-5 2 2 4 0 t-TS4/5 t-TS5/3 t-5 s-TS1/2 -20 CP1 t-2 s-TS2/3 s-TS1/4 s-4 -40 s-3 s-2 s-3 s-1 s-1 t-TS2/3 -60 t-3 t-3 ‡ ‡ ‡ ‡ ‡ -80 J. Phys. Chem. A107, 3107 (2003)

41. . Gracia, J. Andrés, J. R. Sambrano, V. S. Safont, and A. Beltrán VO+ + H2O + C2H4 VO2+ + C2H6 V(OH)2+ + C2H4 + ‡ ‡ ‡ ‡ Organometallics 23, 730 (2004) 50 D G (kcal/mol) s-TS5 t-VO2+ + s-C2H6 s-VO+ + s-H2O + s-C2H4 30 t-TS1/2 t-TS5 t-VO++ s-H2O + s-C2H4 10 t-1 7.3 s-VO2+ s-C2H6 s-TS1/2 s-5 s-V(OH)2+ + s-C2H4 t-TS2/3 s-TS3/4 s-6 -10 s-TS2/3 t-TS3/4 t-6 t-2 s-1 t-5 CP t-V(OH)2+ + s-C2H4 -30 s-2 s-4 -50 t-4 s-3 t-3 -70

42. V(OH)2+ + C3H4 VO2+ + C3H6 VO+ + CO(CH3)2 CHOC2H5 DG (kcal/mol) 20 s-Propanal + s-VO+ s-TS1Ac s-TS2Al s-Acetona + s-VO+ 10 s-propene + S-VO2+ s-TS1P s-TS1Al s-Aleno + s-V(OH)2+ 0 s-1 t-TS2Al t-TS1Ac t-2/3 s-Propanal + t-VO+ -10 t-1Al t-TS1P s-Acetona+ t-VO+ -20 s-TS1Al s-Aleno + t-V(OH)2+ t-1 -30 s-2P s-2 -40 s-3 s-2Ac s-1Al t-2Al -50 t-2P ‡ ‡ -60 s-2Al t-2Ac -70 L. Gracia, J. R. Sambrano, J. Andrés and A. Beltrán Organometallics 25, 1643 (2006) CP

43. D G (kcal/mol) 60 t-NbO3- + H2O t-TS1 t-NbO3(H2O)- 40 43.9 41.5 35.7 t-NbO2(OH)2- 26.0 20 s-NbO3- + H2O 17.9 +O2 1.3 -2.3 -3.7 0 0.0 -1.9 s-NbO3(H2O)- -4.4 -4.0 -12.0 s-TS1 t-TS3 t-NbO5(H2O)- s-NbO5- + H2O -19.2 -12.1 -12.4 -13.4 -23.0 -20 t-TS2 -22.4 +O2 -23.1 t-NbO4(OH)2--A t-NbO4(OH)2--B -40 +O2 -59.0 -60 s-NbO2(OH)2- -80 ‡ ‡ ‡ NbO3- (1A1)+ H2O + O2 (3Sg) NbO5- (1A’)+ H2O CP2 CP1 R. Sambrano, L. Gracia, J. Andrés, S. Berski and A. Beltrán J. Phys. Chem. A108, 10850 (2004)

44. Oxidation of Methanol to Formaldehyde on a Hydrated Vanadia Cluster five-fold V The main effect of hydration can be associated to the destabilization of the methoxy-intermediates P. González-Navarrete, L. Gracia, M. Calatayud and J. Andrés J Comput Chem 31, 2493-2501(2010).

45. Two intermediates, a five-fold coordinate and a tetrahedral vanadium, have been considered with C-H bond breaking barriers of 23.6 kcal/mol and 45.3 kcal/mol respectively. The penta-coordinate species, although it is 11.5 kcal/mol less stable than the tetrahedral one, might be regarded as a potential reactive intermediate Modelo Hidratado Actividad investigadora: Resultados tetrahedral V

46. Int4 TS 29.3 on V=O Int1 17.2 TS 14.9 Int1 4.9 Int4 on V-O-Ti -7.5 The vanadia/titania catalysts on V=O on V-O-Ti • V-O-Ti site leads to lower barrier, more stable dissociation product P. González-Navarrete,L. Gracia, M. Calatayudand J. Andrés J. Phys. Chem. C, Vol. 114, No. 13, 2010

47. Comparison between both B3LYP/6-311G(2d,p) energy profiles. Path1 and Path2. a Broken-symmetry transition states and projected energies. bTriplet intermediates.