I am struggling with the lack of documentation for the NMR calculations. What are the units in the SHIFT files? I find:<div><br></div><div><div>! Conversion factors</div><div><b> <font color="#ff0000">! factor for the CHEMICAL SHIFTS: alpha^2 * ppm.</font></b></div><div><b><font color="#ff0000"> nmr_env%shift_factor = (1.0_dp/137.03602_dp)**2*1.0E+6_dp/cell%deth</font></b></div><div><b><font color="#ff0000"> ! factor for the CHEMICAL SHIFTS: alpha^2 * ppm.</font></b></div><div><b><font color="#ff0000"> nmr_env%shift_factor_gapw = (1.0_dp/137.03602_dp)**2*1.0E+6_dp</font></b></div><div> <font color="#ff0000"> ! chi_factor = 1/4 * e^2/m * a_0 ^2</font></div><div><font color="#ff0000"> nmr_env%chi_factor = 1.9727566E-29_dp/1.0E-30_dp ! -> displayed in 10^-30 J/T^2</font></div><div><font color="#ff0000"> ! Factor to convert 10^-30 J/T^2 into ppm cgs = ppm cm^3/mol</font></div><div><font color="#ff0000"> ! = 10^-30 * mu_0/4pi * N_A * 10^6 * 10^6 [one 10^6 for ppm, one for m^3 -> cm^3]</font></div><div><font color="#ff0000"> nmr_env%chi_SI2ppmcgs = 6.022045_dp/1.0E+2_dp</font></div><div><font color="#ff0000"> ! Chi to Shift: 10^-30 * 2/3 mu_0 / Omega * 1/ppm</font></div><div><font color="#ff0000"> nmr_env%chi_SI2shiftppm = 1.0E-30_dp*8.37758041E-7_dp/ &</font></div><div><font color="#ff0000"> (cp_unit_from_cp2k(cell%deth, "angstrom^3")*1.0E-30_dp)*1.0E+6_dp</font></div><div><br></div><div> IF (output_unit > 0) THEN</div><div> WRITE (output_unit, "(T2,A,T65,ES15.6)") "NMR| Shift gapw radius (a.u.) ", nmr_env%shift_gapw_radius</div><div> IF (nmr_env%do_nics) THEN</div><div> WRITE (output_unit, "(T2,A,T50,I5,A)") "NMR| NICS computed in ", nmr_env%n_nics, " additional points"</div><div> WRITE (output_unit, "(T2,A,T60,A)") "NMR| NICS coordinates read on file ", TRIM(nics_file_name)</div><div> END IF</div><div> WRITE (output_unit, "(T2,A,T65,ES15.6)") "NMR| Shift factor (ppm)", nmr_env%shift_factor</div><div> IF (gapw) THEN</div><div> WRITE (output_unit, "(T2,A,T65,ES15.6)") "NMR| Shift factor gapw (ppm)", nmr_env%shift_factor_gapw</div><div> END IF</div><div> WRITE (output_unit, "(T2,A,T65,ES15.6)") "NMR| Chi factor (SI)", nmr_env%chi_factor</div><div> <span style="background-color: red;"> </span><span style="background-color: white;"><font color="#ff0000">WRITE (output_unit, "(T2,A,T65,ES15.6)") "NMR| Conversion Chi (ppm/cgs)", nmr_env%chi_SI2ppmcgs</font></span></div><div><span style="background-color: white;"><font color="#ff0000"> WRITE (output_unit, "(T2,A,T65,ES15.6)") "NMR| Conversion Chi to Shift", nmr_env%chi_SI2shiftppm</font></span></div><div> END IF</div><div><br></div><div>And in the output of that run:</div><div><br></div><div><div> Inizialization of the NMR environment</div><div><br></div><div> NMR| Shift gapw radius (a.u.) 1.133836E+02</div><div> NMR| Shift factor (ppm) 6.533065E-03</div><div> NMR| Shift factor gapw (ppm) 5.325134E+01</div><div> NMR| Chi factor (SI) 1.972757E+01</div><div> <b>NMR| Conversion Chi (ppm/cgs) 6.022045E-02</b></div><div><b> NMR| Conversion Chi to Shift 6.935882E-04</b></div><div><br></div><div>So to convert the numbers in the SHIFT files is the correct conversion is <b>6.022045E-02 or </b><b>6.935882E-04? </b></div></div><div><b><br></b></div><div><b>Thank you!</b></div><div><b><br></b></div><div><b>Sincerely,</b></div><div><b><br></b></div><div><b>Ron Cohen</b></div><div><b><br></b></div><br></div>
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