Electronic Supplementary Information

Transcription

1 Electronic Supplementary Information Xenon as a mediator of chemical reactions? ( ) by Dominik Kurzydłowski and Wojciech Grochala Contents. 1. Unit cell vectors, fractional atomic coordinates and enthalpy for T1, T2, T3, T4, O1, O2, O3, O4, O5, H1, and C1 structures, as optimized with CASTEP at p=5 GPa (300 ev cutoff, 0.05 Å 1 k-point grid). 2. Imaginary phonon frequencies at Γ for the O4 structure, as optimized with VASP at p=15 GPa. 3. Unit cell vectors, fractional atomic coordinates and enthalpy for M1 structure, as optimized with CASTEP at p=5 GPa (300 ev cutoff, 0.05 Å 1 k-point grid). 4. Unit cell vectors, fractional atomic coordinates and enthalpy for XeF 2, Xe, AuF 3 and Au, as optimized with CASTEP at p=5 GPa (300 ev cutoff, 0.05 Å 1 k-point grid). 5. Unit cell vectors, fractional atomic coordinates, and enthalpy for M1 and M2 structures, as optimized with CASTEP at p=5 GPa (increased accuracy, 600 ev cutoff, 0.04 Å 1 kpoint grid). 6. Population analysis and the closest interatomic separations for M1 structure, as optimized with CASTEP at p=5 GPa (increased accuracy, 600 ev cutoff, 0.04 Å 1 kpoint grid). 7. Phonon wavenumbers (ν) at Γ for the M1 structure at p=5 GPa. 8. Phonon dispersion, DOS and atomic contributions to DOS for the M1 structure at p=5 GPa. 9. Plot of enthalpy for all structures studied for 5 GPa p 100 GPa. 10. Estimate of the formation pressure of XeAuF using the common tangent method (increased accuracy, 600 ev cutoff, 0.04 Å 1 k-point grid). 11. References to VASP, PHONON and CASTEP. 1

2 1. Unit cell vectors, fractional atomic coordinates and enthalpy for T1, T2, T3, T4, O1, O2, O3, O4, O5, H1, and C1 structures, as optimized with CASTEP at p=5 GPa (300 ev cutoff, 0.05 Å 1 k-point grid). Structure Enthalpy Unit cell vectors /Å Au(x,y,z) F(x,y,z) Xe(x,y,z) /ev T1 (P4/nmm) a = c = T2 (P4/nmm) a = c = T3 (I4mm) a = c = T4 (P4/mmm) a = c = O1 (Pnma) a = b = c = O2 (Cmcm) a = b = c = O3 (Pnma) a = b = c = O4 (Pmmn) a = b = c = O5 (Cmcm) a = b = c = H1 (P6 3 /mmc) a = c = γ = C1 (F4-3m) a =

3 1 Structure analogous to the structure of LaOI (LaOI type), structure has not convered for p=5 GPa and data for 10 GPa is shown; 2 BaFI type; 3 XeF 2 type; 4 hypothetical structure containing layers of XeAuF stoichometry; 5 HgClBr type; 6 RbAuS type; 7 RbAuTe type; 8 InOBr type; 9 OCAuCl type; 10 structure analogous to the high pressure phase of RbAuTe; 11 HgF 2 type. 2. Imaginary phonon frequencies at Γ for the O4 structure, as optimized with VASP at p=15 GPa. Structure Imaginary phonons /cm -1 O4 54; 5* * Deviation from 0 cm 1 for phonons with wavenumbers 5 cm 1 < ν < +5 cm 1 is within accuracy of the computational method. C1 and C2 do not have imaginary phonons at Γ. 3. Unit cell vectors, fractional atomic coordinates and enthalpy for M1 structure, as optimized with CASTEP at p=5 GPa (300 ev cutoff, 0.05 Å 1 k-point grid). Structure Enthalpy /ev Unit cell vectors /Å Au(x,y,z) F(x,y,z) Xe(x,y,z) M1 (P2 1 /m) * a = b = c = β = * derived form O4 following an imaginary phonon (-70 cm -1 ) at T point (at 15 GPa). 4. Unit cell vectors, fractional atomic coordinates and enthalpy for XeF 2, Xe, AuF 3 and Au, as optimized with CASTEP at p=5 GPa (300 ev cutoff, 0.05 Å 1 k-point grid). Structure Enthalpy /ev Unit cell vectors /Å Au(x,y,z) F(x,y,z) Xe(x,y,z) Xe (Fm3m) a = n.a. n.a XeF 2 (I4mm) a = n.a c = Au (Fm3m) a = n.a. n.a. AuF 3 (P6 1 22) a = c = γ = n.a. 3

4 5. Unit cell vectors, fractional atomic coordinates, and enthalpy for M1 structure, as optimized with CASTEP at p=5 GPa (increased accuracy, 600 ev cutoff, 0.04 Å 1 kpoint grid). Structure Enthalpy /ev Unit cell vectors /Å Au(x,y,z) F(x,y,z) Xe(x,y,z) M a = b = c = β = M2 (P2 1 /m)* a = b = c = β = * the M1 type where Xe and Au atoms were exchanged with each other to yield an initial Au Xe(II) F structure, which has converged back to the XeAu(I)F isomer. 6. Population analysis and the closest interatomic separations for M1 structure, as optimized with CASTEP at p=5 GPa (increased accuracy, 600 ev cutoff, 0.04 Å 1 kpoint grid). Structure q(au) /e q(f) /e q(xe) /e R(AuF) /Å R(AuXe) /Å R(AuAu) /Å M

5 7. Phonon wavenumbers (ν) at Γ for the M1 structure at p=5 GPa. ν /cm 1 Assignement Symmetry IR/Raman -2 Acoustic (y) A u +/- -2 Acoustic (x) B u +/- -1 Acoustic (z) B u +/- 43 Hindered rotation of XeAuF units around z axis B g -/+ 54 Bending of XeAuF units (y)* A u +/- 54 Bending of XeAuF units (z) B u +/- 59 Hindered rotation of XeAuF units around y axis A g -/+ 67 Hindered translation in the x direction # A g -/+ 82 Bending of XeAuF units (y) + B g -/+ 103 Bending of XeAuF units (z) + A g -/+ 134 Bending of the AuF bond (y) A u +/- 144 Bending of the AuF bond (y) B g -/+ 160 Stretching of the AuXe bond** B u +/- 169 Stretching of the AuXe bond ## A g -/+ 186 Bending of the AuF bond (z) B u +/- 197 Bending of the AuF bond (z) A g -/+ 443 Stretching of the AuF bond** B u +/- 469 Stretching of the AuF bond ## A g -/+ *atoms move in y direction; # accompanied by puckering of the Au plane; + large amplitude for the movement of Au atoms which leads to 2+2 coordination of Au atoms by other Au atoms **antisymmetric with respect to the other molecule in the unit cell; ## symmetric with respect to the other molecule in the unit cell 5

6 8. Phonon dispersion, DOS and atomic contributions to DOS for the M1 structure at p=5 GPa. The lowest frequency optical phonons are difficult to predict correctly. The quasi imaginary feature seen for a single branch in the spectrum above (between G and B and partly between B and A) is not in fact imaginary, since following this distortion does not lead to any even minor improvement in energy. We anticipate that a quasi imaginary character of this mode is related to insufficient size of the supercell chosen for the calculation (which is limited by computational resources available). 6

7 9. Plot of enthalpy for all structures studied for 5 GPa p 100 GPa C1 T1 T2 T3 T4 O1 H [ev per molecule] O2 O3 O4 H1 M p [GPa] 10. Estimate of the formation pressure of XeAuF using the common tangent method (increased accuracy, 600 ev cutoff, 0.04 Å 1 k-point grid). 1/3AuF 3 +2/3Au+Xe XeAuF 5 GPa = 0.33 ev 5 GPa = 4.92 Å 3 P(formation) = x H/ V = 15.8 GPa Product (XeAuF) was assumed to adopt the M1 structure. 11. References to VASP, PHONON and CASTEP. VASP: Kresse, G.; Futhmuller, J.; Phys. Rev. B, 54, (1996); Kresse, G.; Futhmuller, J.; Comput. Mater. Sci. 6, (1996); Kresse, G.; Joubert, D.; Phys. Rev. B, 59, (1999). CASTEP: M. D. Segall, P. J. D. Lindan, M. J. Probert, C. J. Pickard, P. J. Hasnip, S. J. Clark, M. C. Payne, J. Phys.: Cond. Matt. 14(11) (2002). PHONON: Parlinski, K.; Li, Z. Q.; Kawazoe, Y. Phys. Rev. Lett. 78, (1997). 7