Theoretical calculations of NMR/EPR parameters

1. Theoretical calculations of NMR/EPR parameters Exercises Michal Straka 17.7.2003 Assisted by Christian Remenyi and Alexander Panchenko

2. Motivation • Why do we need calculations? • To complement, support, confirm experiment • To calculate immeasurable • To understand • To predict

3. What can be calculated? • NMR/EPR parameters: • g-tensors • Chemical shifts, including SO correction • Spin-spin coupling • Hyperfine coupling, including SO correction • Zero-field splitting (coming soon) • Analysis in terms of orbitals, spin density etc. • Generally single gas-phase molecule, but: • Solvation effects (HFC) possible • Molecular dynamics (shots from MD) possible

4. Software (selection) • Common packages • Gaussian www.gaussian.com • Turbomole www.turbomole.com • ADF www.scm.com, Aces II www.qtp.ufl.edu/Aces2 • Our wavefunction packages + property codes • deMon(www.deMon-software.com) + Master • Respect + Mag • Our special interfaces • GS2RS, DEM2MAG,TM2MAG • Visualization packages • Molden (www.cmbi.kun.nl/~schaft/molden) • Molekel (www.cscs.ch/molekel)

5. Possibilities CS - chemical shift SOCS – spin-orbit chemical shift SSC – spin-spin coupling HFC - hyperfine coupling SOHFC – spin-orbit hyperfine coupling GT – g-tensor ZFS – zero-field splitting

6. Calculations • We should know which method, level ofapproximation, basis set ,and code to use to get desiredaccuracy in reasonable time. • Depends of size and type of system • Carbohydrates easy, actinides difficult (rel.+ corr.) • Might be simple: CS or HFC with Gaussian 98 • One input , one run • Might be complicated: MD simulations of g-tensor of the semibenzoquinon radical anion in water (James Asher) • CPMD (dymanics)>TURBOMOLE(calculate WF of shots)>TM2MAG(interface)>MAG(g-tensor)

7. Praktikum • Login: “ssh gks@132.187.24.21”, then “ssh mk62” • For password write mail to straka@mail.uni-wuerzburg.de • Current password valid till end of July, then e-mail me • Linux comands “ls” list, “cd” change dir, “cp” copy. For more, see linux_small.ps in ~/Documentation • Policy: • Always make special directory with your name and do everything there • mkdir ~/remenyi;cd remenyi • Or use one of the student? directories • “cd;cd student4/seminar2003” • See /home/straka/dqs how to run specifically in queue • “qsub –q machine Job” • “qstat -f” shows jobs in queue • Longer jobs (>1h) always to the queue, see also /home/prog/OUR_HAREM • Documentation: is in ~/Documentation • Linux book, using vi, DFT theory and this document • scp –r Documentation mylogin@myhost:mydir

8. Exercise 1 :Calculating HFC of nitrogen atom • Use different programs to calculate HFC on N atom • Gaussian 98 > GS2RS > MAG • Respect + Mag • Gaussian 98 does not calculate SO correction, but knows more functionals • Use Gaussian 98 to see the method dependence • Possible methods HF, BP86, BLYP, BPW91, B3P86, B3LYP, B3PW91, MP2 • Use IGLO-II basis set • Optional: Use Gaussian 98 to see basis set dependence

9. Doing exercise 1 (~/seminar2003/HYPERFINE_N_ATOM) • HFC with Gaussian 98 • Have a look at Gaussian input (less hf_n) • Look into Job file (JobHFCG98) • Run Gaussian Job (./JobHFCG98) • Have a look at output (less hf_n.out) • Try different functional (optional, look in TASK file) • SO correction to HFC • Run makefchk (makefchk hf_n) • Run GS2RS interface(GS2RS-FC hf_n) • Look at produced input (hf_n.out) and at SOHFC.M • Run Job(./JobHFCMAG) • Have a look at output (less *OUT*) • HFC with Respect + Mag (./SO) • Look at input for Respect (less so-resp.inp) • Run Job (./JobHFCSO) • Have a look at input for Mag and both outputs(less SOHFC.M, less *.out, less *OUT*)

10. Exercise 2: Chemical shifts, SO correction • Optimize geometry of HCCI at B3LYP/SDDAll level using Gaussian 98 • Use optimized geometry to calculate chemical shifts in HCCI, suppose 13C • Using Gaussian, GIAO, IGLO-II basis set • Using deMon+Master and common gauge origin on iodine, IGLO-II basis set • Calculate spin-orbit chemical shifts of 1H and 13C atoms in HCCI • Use deMon+Master, IGLO-II basis set, and common gauge origin on iodine

11. Doing exercise 2(~/seminar2003/CSHIFTS) • Geometry optimization with Gaussian • Prepare Z-matrix, look at optgeo input (Molden, less optgeo) • Run it first with JobOPTGEO (./JobOPTGEO) • Look at optgeo.out (less optgeo.out) • NMR with Gaussian • Copy optgeo.chk to cs.chk, run JobCS(cp optgeo.chk cs.chk;./JobCS) • Meanwhile look at input (less cs_giao) • Look at output cs_giao.out(less cs_giao.out) • 32.34-30.58=1.76, exp. +2.23 • NMR with deMon + Master (./demon) • Run ./JobCS • Get optimized xyz, put into hcci.inp, look at hcci.inp(less hcci.inp) • Look at output, for H atom 31.02-28.36=+2.66, exp. +2.23 • SO NMR with deMon + Master (./SO) • Look at so4.inp, run JobSO, look at COMM_I.M • Look at so4.out, so4*OUT* • H atom, exp=+2.23; we get 31.02-28.36-(-0.53)=3.19 • or 32.24-30.58-(-0.53)=2.19

12. Exercise 3:Optional • Look at each exercise we tried and find TASK files inside, there you find some additional exercises • Find exercises from 2002 in /home/prog/Documentation/GK_theory.doc and try to work them out

13. Acknowledgement • Martin Kaupp • Christian Remenyi • Alexander Panchenko • Herbert Dilger