1. Quantum Mechanical Prediction of the Existence of Rare Gas-bound Species Katheryn Shi 1, Brent Wilson 2, Angela K. Wilson 3 1 TAMS, University of North Texas 2 Department of Chemistry, University of North Texas 3 Faculty Mentor, Department of Chemistry, University of North Texas

2. Introduction Computational chemistry: combines math, chemistry, and computer science to solve chemical problems Computational chemistry may be used where laboratory work is impractical Dangerous compounds Molecules difficult to isolate Trying to solve the Schrödinger equation and obtain properties (e.g. optimal geometries, vibrational frequencies, charge distributions, dissociation energies, etc.)

3. Introduction HΨ=EΨ – Schrödinger Equation H – Hamiltonian Operator Ψ – Wave function E – Eigenvalue (energy)

4. Introduction Before the 1960’s, rare gases (noble gases)were considered inert. XePtF 6 was synthesized by Neil Bartlett in 1962*, opening a new area of exploration More recently, organic rare gas compounds have been prepared (HXeCCH †, HXeCC †, HKrCCH, etc.) *Bartlett, N. "Xenon hexafluoroplatinate Xe+[PtF6]?" Proceedings of the Chemical Society of London. 1962: 218. † Khriachtchev, Leonid, Hanna Tanskanen, Jan Lundell, Mika Pettersson, Harri Kiljunen, and Markku Räsänen. "Fluorine-Free Organoxenon Chemistry: HXeCCH, HXeCC, and HXeCCXeH." J. Am. Chem. Soc.. 125 (16) (2003): [4696–4697 ].

5. Research Goal Discover new rare-gas compounds with useful properties

6. Method versus Basis Set Hartree-Fock DFT MP2CISD CCSD QCISD(T) CCSD(T) MP4 Full CI “Exact” solution to H  =E  Basis Set Size Method DZ TZ QZ 5Z 6Z ∞

7. Methodology B3LYP Type of density functional Total energy expressed as a function of electron density Not wave function based Second-order Møller-Plesset perturbation theory (MP2) Begins with Hartree Fock calculation and adds in energy to account for electron correlation

8. Methodology CCSD(T) Includes higher excitations and recovers more correlation energy than MP2

9. Methodology Basis sets Set of functions representing atomic orbitals Used to describe the character of the electrons in atoms or molecules Correlation consistent basis sets aug-cc-pVnZ (n = D, T, Q) Designed to systematically recover correlation energy with increase in size

10. Procedure Geometry Optimizations Try to find a minimum on the potential energy (PE) surface Frequency Calculations Make sure there are no imaginary frequencies to confirm PE minimum

11. Procedure Start with B3LYP Less computationally expensive False positives Check molecules that converged using B3LYP with more sophisticated methods, such as MP2 and CCSD(T)

12. Molecules Tested HArN HKrN ArCAr ArCCAr ArCCCAr FArKr FKrAr FKrN HArCCCN HArKr HArO HeCCHe HKrAr HKrCCCN HKrKr HKrNe HKrS HKrSe KrCCCKr KrCCKr HArBr HArCl HCCKrN NKrCCCN FArCCCN FKrCCCN FArCCArCCArF FKrCCKrCCCKrCCKrF BrKrCCKrBr BrKrGeGeKrBr ClArCArCCCArCArCl ClArCCArCl ClArCCCArCl ClKrPPKrCl ClNeCCCNeCl HCCArN NArCCCN HArP ClArCCArCCArCl ClArSiSiArCl FArN FKrCKrCCCKrCKrF

13. Molecules Tested FKrKrCCCKrKrF FNeCCCNeF HArCCCCN HArCCN HCArN HCCCArN HCCCKrN HCKrN KrCKr NArCCCCN NKrCCCCN ClKrCCKrCl ClNeCCNeCCNeCl ClNeCCNeCl HeCHe HKrCCCCCN HKrCCCCN HKrCCKrH HKrCCN HKrO Br(CKr) 6 HArAs HKrP Kr(CH) 6 Kr(CO) 6 Kr 2 SO 4 Kr 4 SO 4 ClNeCNeCCCNeCNeCl FArCCArF FArCCCCCN FKrCCCCCN FKrCCKrCCKrCCKrF FKrCCKrCCKrF FKrS FKrSiCKrF FKrSiSiKrF FNeCCNeCCNeF FNeCCNeF FNeCNeCCCNeCNeF HArCCCCCN HeCCCHe

14. Potential New Rare Gas Molecules

15. Results HArNHKrN MethodBasis SetH–ArAr–NH–KrKr–N B3LYP aug-cc-pV n Z n = D 1.2832.1401.4262.163 n = T 1.5782.2201.4192.135 n = Q 1.5662.2081.6642.240 MP2 aug-cc-pV n Z n = D 1.2712.1961.4092.215 n = T 1.2592.1081.3992.131 n = Q 1.2582.0871.4002.108 CCSD(T) aug-cc-pV n Z n = D 1.2972.2611.4522.294 n = T 1.2722.1851.4252.220 n = Q 1.2702.1651.4252.202

16. Results

17. Conclusions HArN and HKrN were predicted to be stable Frequency calculations indicated the geometries were minimum energy points Bond lengths converged with increasing basis set size Bond length analysis indicated covalent properties Contain nitrogen - unique

18. Interest in noble gas molecules due to laser action 354nm laser discovered using XeF in 1975 Applications

19. HArN and HKrN were predicted to be stable Medicine Anti-tumor agents Laser eye surgery Industry Excimer lasers for semiconductor manufacturing

20. Acknowledgements Prof. Angela Wilson Brent Wilson Dr. Mike Drummond Dr. Jamal Uddin Dr. Wanyi Jiang The Wilson Group National Science Foundation Department of Education (CASCaM) National Center for Supercomputing Applications University of North Texas Faculty Research Grant Academic Computing Services for UNT Research Cluster Texas Academy of Mathematics and Science