Wall clock time and date at job start Sat Mar 6 2021 07:51:45 AMSOL-version 7.1 by G. D. Hawkins, D. J. Giesen, G. C. Lynch, C. C. Chambers, I. Rossi, J. W. Storer, J. Li, J. D. Thompson, P. Winget, B. J. Lynch, D. Rinaldi, D. A. Liotard, C. J. Cramer, and D. G. Truhlar Copyright 2004 by Regents of the University of Minnesota. All rights reserved. Notice: recipients of this code are asked to comply with the user agreement in Section 1 of the documentation file. ******************************************************************************* * 1SCF - SCF CALCULATION WITHOUT GEOMETRY OPTIMIZATION * - USE EF ROUTINE FOR MINIMUM SEARCH (DEFAULT) * GEO-OK - OVERRIDE INTERATOMIC DISTANCE CHECK * TLIMIT= - A TIME OF 15. SECONDS REQUESTED * CHARGE - CHARGE ON SYSTEM= 0 * AM1 - THE AM1 HAMILTONIAN TO BE USED * DEV - DEVELOPER OPTIONS ARE ALLOWED * SM5.42R - SM5.42R CALCULATIONS WILL BE PERFORMED * - CHARGE MODEL 2 WILL BE USED (CM2A) * - THE SOLVENT IS USER-SPECIFIED * DIELEC - THE SOLVENT DIELECTRIC CONSTANT IS 2.06 * IOFR - THE SOLVENT INDEX OF REFRACTION IS 1.4345 * ALPHA - THE SOLVENT ALPHA IS 0.00 * BETA - THE SOLVENT BETA IS 0.00 * GAMMA - THE SOLVENT MACROSCOPIC SURFACE TENSION IS * 38.93 CAL MOL^-1 ANGSTROM^-2 * FACARB - THE FRACTION OF AROMATIC CARBONS IS 0.00 * FEHALO - THE FRACTION OF ELECTRONEGATIVE HALOGENS IS 0.00 ******************************************************************************* Atom NO. Chemical Bond length Bond angle Dihedral angle number (k) symbol (angstroms) (degrees) (degrees) (I) NA:I NB:NA:I NC:NB:NA:I NA NB NC 1 1 C 2 2 Si 1.86297 * 1 3 3 C 1.86304 * 109.93107 * 2 1 4 4 C 1.87380 * 109.94896 * 121.17608 * 2 1 3 5 5 C 1.53716 * 107.28073 * 73.84640 * 4 2 1 6 6 C 1.52523 * 109.64415 * 59.12685 * 5 4 2 7 7 C 1.52520 * 111.65421 * 283.00921 * 6 5 4 8 8 C 1.50701 * 109.44205 * 197.04279 * 7 6 5 9 9 O 1.20833 * 119.99854 * 239.93330 * 8 7 6 10 10 O 1.34229 * 120.00236 * 59.92805 * 8 7 6 11 11 C 1.45200 * 116.99914 * 180.02562 * 10 8 7 12 12 C 1.50698 * 109.46850 * 180.02562 * 11 10 8 13 13 C 1.37828 * 120.04408 * 0.02562 * 12 11 10 14 14 C 1.38833 * 120.70799 * 179.97438 * 13 12 11 15 15 Br 1.89096 * 119.86424 * 179.97438 * 14 13 12 16 16 C 1.37848 * 120.27240 * 359.97438 * 14 13 12 17 17 C 1.39385 * 119.52708 * 0.03824 * 16 14 13 18 18 C 1.38979 * 120.04025 * 179.97438 * 12 11 10 19 19 O 1.34876 * 120.98438 * 0.02562 * 18 12 11 20 20 C 1.33714 * 122.41461 * 179.71665 * 19 18 12 21 21 C 1.34542 * 122.84717 * 0.58529 * 20 19 18 22 22 C 1.50701 * 120.20411 * 179.72609 * 21 20 19 23 23 O 1.42895 * 109.47079 * 249.72686 * 22 21 20 24 24 Si 1.86301 * 109.47149 * 9.72181 * 22 21 20 25 25 H 1.48506 * 109.47302 * 59.99966 * 24 22 21 26 26 H 1.48503 * 109.47334 * 300.00099 * 24 22 21 27 27 H 1.48500 * 109.47376 * 180.02562 * 24 22 21 28 28 C 1.41994 * 119.59126 * 359.44766 * 21 20 19 29 29 O 1.21920 * 121.40853 * 180.23321 * 28 21 20 30 30 C 1.53715 * 109.61310 * 77.00715 * 7 6 5 31 31 H 1.08990 * 109.47498 * 298.82366 * 1 2 3 32 32 H 1.09003 * 109.46999 * 58.82761 * 1 2 3 33 33 H 1.09003 * 109.46949 * 178.82051 * 1 2 3 34 34 H 1.09003 * 109.47158 * 181.17085 * 3 2 1 35 35 H 1.08992 * 109.47271 * 301.17280 * 3 2 1 36 36 H 1.09001 * 109.46473 * 61.17813 * 3 2 1 37 37 H 1.08997 * 109.89401 * 314.40419 * 4 2 1 38 38 H 1.09000 * 109.96034 * 193.32416 * 4 2 1 39 39 H 1.09000 * 109.44001 * 299.07228 * 5 4 2 40 40 H 1.08999 * 109.41356 * 179.16209 * 5 4 2 41 41 H 1.08998 * 109.04143 * 162.44665 * 6 5 4 42 42 H 1.08997 * 109.04250 * 43.56678 * 6 5 4 43 43 H 1.08996 * 109.44606 * 316.96937 * 7 6 5 44 44 H 1.09006 * 109.47008 * 60.00133 * 11 10 8 45 45 H 1.08994 * 109.47577 * 300.00277 * 11 10 8 46 46 H 1.08004 * 119.64441 * 359.97438 * 13 12 11 47 47 H 1.08005 * 120.23498 * 180.02562 * 16 14 13 48 48 H 1.08000 * 118.57688 * 180.29086 * 20 19 18 49 49 H 1.09001 * 109.47380 * 129.72083 * 22 21 20 50 50 H 0.96696 * 114.00435 * 59.99627 * 23 22 21 51 51 H 1.08998 * 109.89380 * 60.30020 * 30 7 6 52 52 H 1.09005 * 109.89473 * 181.41145 * 30 7 6 Note: An asterisk (*) indicates this parameter was or will be optimized. Cartesian coordinates (angstroms) NO. Atom X Y Z 1 6 0.0000 0.0000 0.0000 2 14 1.8630 0.0000 0.0000 3 6 2.4981 1.7514 0.0000 4 6 2.5023 -0.9118 1.5070 5 6 2.2742 -2.4123 1.2636 6 6 3.0139 -2.8454 0.0020 7 6 2.2742 -2.4142 -1.2602 8 6 2.7914 -3.1996 -2.4378 9 8 3.2920 -2.6240 -3.3749 10 8 2.6962 -4.5385 -2.4456 11 6 3.2157 -5.2294 -3.6122 12 6 3.0226 -6.7145 -3.4437 13 6 2.4270 -7.2079 -2.3029 14 6 2.2419 -8.5733 -2.1335 15 35 1.4226 -9.2243 -0.5585 16 6 2.6529 -9.4566 -3.1089 17 6 3.2567 -8.9691 -4.2667 18 6 3.4441 -7.5882 -4.4389 19 8 4.0289 -7.1289 -5.5642 20 6 4.4500 -7.9437 -6.5371 21 6 4.3150 -9.2811 -6.4784 22 6 4.8060 -10.1432 -7.6128 23 8 3.6879 -10.7074 -8.3007 24 14 5.8031 -9.1048 -8.7953 25 1 6.9651 -8.5183 -8.0805 26 1 4.9520 -8.0140 -9.3350 27 1 6.2864 -9.9541 -9.9135 28 6 3.7124 -9.8756 -5.3384 29 8 3.5773 -11.0840 -5.2486 30 6 2.5030 -0.9141 -1.5053 31 1 -0.3634 0.4954 0.9002 32 1 -0.3633 0.5320 -0.8793 33 1 -0.3633 -1.0275 -0.0212 34 1 3.5879 1.7428 -0.0210 35 1 2.1219 2.2743 -0.8792 36 1 2.1561 2.2618 0.9004 37 1 1.9547 -0.5925 2.3937 38 1 3.5664 -0.7148 1.6375 39 1 1.2078 -2.6022 1.1422 40 1 2.6488 -2.9787 2.1163 41 1 3.1132 -3.9309 0.0029 42 1 4.0081 -2.3987 0.0017 43 1 1.2077 -2.6033 -1.1382 44 1 4.2780 -5.0107 -3.7209 45 1 2.6826 -4.8927 -4.5013 46 1 2.1008 -6.5249 -1.5324 47 1 2.5082 -10.5187 -2.9767 48 1 4.9145 -7.5092 -7.4099 49 1 5.4308 -10.9438 -7.2167 50 1 3.0875 -10.0512 -8.6802 51 1 3.5674 -0.7175 -1.6343 52 1 1.9559 -0.5955 -2.3926 RHF calculation, no. of doubly occupied orbitals= 73 REFERENCES FOR PARAMETERS IN GAS-PHASE HAMILTONIAN: H: (AM1): M.J.S. DEWAR ET AL, J. AM. CHEM. SOC. 107 3902-3909 (1985) C: (AM1): M.J.S. DEWAR ET AL, J. AM. CHEM. SOC. 107 3902-3909 (1985) O: (AM1): M.J.S. DEWAR ET AL, J. AM. CHEM. SOC. 107 3902-3909 (1985) Si: (AM1): M.J.S.DEWAR, C. JIE, ORGANOMETALLICS, 6, 1486-1490 (1987). Br: (AM1): M.J.S. DEWAR AND E. G. ZOEBISCH, THEOCHEM, 180, 1 (1988). REFERENCE FOR CHARGE MODEL 2: J. Li, J. Xing, C. J. Cramer, and D. G. Truhlar, J. Chem. Phys. 111 (1999) 885. REFERENCE FOR THE PARAMETERIZATION OF THE SM5.42R SOLVATION MODEL: J. Li, T. Zhu, G. D. Hawkins, P. Winget, D. A. Liotard, C. J. Cramer, and D. G. Truhlar, Theor. Chem. Acc. 103 (1999) 9-63 P. Winget, J. D. Thompson C. J. Cramer,and D. G. Truhlar, J. Phys. Chem. B. submitted. CHARGE=0 AM1 1SCF TLIMIT=15 GEO-OK SM5.42R & SOLVNT=GENORG IOFR=1.4345 ALPHA=0.00 BETA=0.00 GAMMA=38.93 & DIELEC=2.06 FACARB=0.00 FEHALO=0.00 DEV s_1458_17845584_484008.mol2 52 1SCF WAS SPECIFIED, SO GEOMETRY OPTIMIZATION WAS NOT USED SCF FIELD WAS ACHIEVED Wall clock time and date at job start Sat Mar 6 2021 07:51:45 Heat of formation + Delta-G solvation = -179.438801 kcal Electronic energy + Delta-G solvation = -36181.423004 eV Core-core repulsion = 31281.663331 eV Total energy + Delta-G solvation = -4899.759673 eV No. of doubly occupied orbitals = 73 Molecular weight (most abundant/longest-lived isotopes) = 468.065 amu Computer time = 1.44 seconds Orbital eigenvalues (eV) -43.34835 -41.73725 -40.04408 -39.88000 -38.10188 -37.78997 -37.20219 -34.60190 -33.66101 -33.13483 -32.43908 -30.69780 -29.47197 -28.54325 -28.46276 -27.47787 -27.29784 -26.00305 -24.91914 -24.41192 -22.51976 -22.21827 -21.26015 -20.66701 -19.61237 -19.08131 -18.66508 -17.99258 -17.76435 -17.63710 -17.41294 -16.69310 -16.47492 -16.25579 -16.18783 -15.85962 -15.79353 -15.49860 -15.43983 -15.11202 -14.71115 -14.59199 -14.49844 -14.39203 -14.20285 -14.11181 -13.95721 -13.93096 -13.79511 -13.47029 -13.35549 -13.26467 -13.22123 -12.83395 -12.64876 -12.54393 -12.40902 -12.25642 -12.24309 -12.03729 -11.95738 -11.92712 -11.79702 -11.50742 -11.45977 -11.16320 -10.92426 -10.73291 -10.69485 -10.43807 -10.40075 -10.35941 -9.55400 -0.81422 -0.68712 0.01441 0.37241 0.86563 0.91869 1.13031 1.15475 1.26067 1.26678 1.46788 1.69968 1.71273 1.74016 1.80486 2.34406 2.48236 2.72813 2.89289 3.08493 3.20153 3.38541 3.50809 3.64059 3.65938 3.70863 3.80301 3.83630 3.91767 4.03629 4.07687 4.11483 4.14599 4.26634 4.28844 4.29380 4.50126 4.58629 4.62794 4.64067 4.65312 4.67720 4.67958 4.68480 4.74422 4.80294 4.82579 4.93852 5.02848 5.05774 5.19498 5.27578 5.31288 5.33889 5.44405 5.48017 5.72873 6.44425 6.47576 6.67971 Net atomic charges, atomic populations, and dipole contributions calculated with CM2 Atom NO. Type Charge No. of electrons 1 C -0.448 4.448 2 Si 1.002 2.998 3 C -0.447 4.447 4 C -0.408 4.408 5 C -0.106 4.106 6 C -0.125 4.125 7 C -0.064 4.064 8 C 0.467 3.533 9 O -0.498 6.498 10 O -0.357 6.357 11 C 0.117 3.883 12 C -0.105 4.105 13 C -0.012 4.012 14 C -0.120 4.120 15 Br -0.024 7.024 16 C 0.002 3.998 17 C -0.211 4.211 18 C 0.161 3.839 19 O -0.212 6.212 20 C 0.130 3.870 21 C -0.310 4.310 22 C -0.053 4.053 23 O -0.527 6.527 24 Si 0.927 3.073 25 H -0.241 1.241 26 H -0.244 1.244 27 H -0.236 1.236 28 C 0.434 3.566 29 O -0.437 6.437 30 C -0.396 4.396 31 H 0.071 0.929 32 H 0.070 0.930 33 H 0.069 0.931 34 H 0.070 0.930 35 H 0.069 0.931 36 H 0.070 0.930 37 H 0.077 0.923 38 H 0.077 0.923 39 H 0.067 0.933 40 H 0.069 0.931 41 H 0.077 0.923 42 H 0.074 0.926 43 H 0.112 0.888 44 H 0.094 0.906 45 H 0.093 0.907 46 H 0.162 0.838 47 H 0.156 0.844 48 H 0.196 0.804 49 H 0.124 0.876 50 H 0.373 0.627 51 H 0.086 0.914 52 H 0.084 0.916 For the charges calculated by CM2: Dipole moment (debyes) X Y Z Total from point charges -0.020 5.350 1.311 5.508 Note: The Mulliken population analysis charges presented below were not used in the solvation calculation but are provided for completeness. The chosen solvation model uses CM2 partial charges for calculating solvation energies. Net atomic charges, atomic populations, and dipole contributions using Mulliken population analysis Atom NO. Type Charge No. of electrons 1 C -0.556 4.556 2 Si 1.197 2.803 3 C -0.555 4.555 4 C -0.494 4.494 5 C -0.143 4.143 6 C -0.162 4.162 7 C -0.083 4.083 8 C 0.310 3.690 9 O -0.384 6.384 10 O -0.274 6.274 11 C 0.043 3.957 12 C -0.106 4.106 13 C -0.032 4.032 14 C -0.200 4.200 15 Br 0.062 6.938 16 C -0.018 4.018 17 C -0.214 4.214 18 C 0.116 3.884 19 O -0.116 6.116 20 C 0.064 3.936 21 C -0.313 4.313 22 C -0.163 4.163 23 O -0.331 6.331 24 Si 0.747 3.253 25 H -0.164 1.164 26 H -0.168 1.168 27 H -0.159 1.159 28 C 0.316 3.684 29 O -0.315 6.315 30 C -0.480 4.480 31 H 0.090 0.910 32 H 0.089 0.911 33 H 0.088 0.912 34 H 0.089 0.911 35 H 0.089 0.911 36 H 0.089 0.911 37 H 0.096 0.904 38 H 0.096 0.904 39 H 0.086 0.914 40 H 0.088 0.912 41 H 0.096 0.904 42 H 0.093 0.907 43 H 0.129 0.871 44 H 0.112 0.888 45 H 0.111 0.889 46 H 0.180 0.820 47 H 0.174 0.826 48 H 0.213 0.787 49 H 0.142 0.858 50 H 0.220 0.780 51 H 0.105 0.895 52 H 0.103 0.897 Dipole moment (debyes) X Y Z Total from point charges 0.571 4.773 1.221 4.960 hybrid contribution -0.215 0.213 -0.462 0.552 sum 0.355 4.986 0.759 5.056 Atomic orbital electron populations 1.26112 1.20266 1.04549 1.04665 0.79522 0.67390 0.67027 0.66326 1.26062 1.06441 1.18463 1.04577 1.26318 1.06399 1.02449 1.14241 1.21164 1.00468 0.95855 0.96803 1.21515 0.99960 1.02413 0.92322 1.20941 1.02223 0.94155 0.90957 1.24048 0.75955 0.80226 0.88780 1.90691 1.40627 1.70506 1.36609 1.86418 1.75305 1.21910 1.43761 1.21485 1.00778 0.86176 0.87270 1.18812 1.04319 0.93878 0.93636 1.21058 0.92496 0.93580 0.96050 1.21848 1.06798 0.95207 0.96123 1.96847 1.79339 1.87530 1.30081 1.21142 0.90325 1.01063 0.89226 1.20731 1.08241 0.92709 0.99719 1.18899 0.93392 0.91411 0.84708 1.83094 1.64948 1.38972 1.24582 1.23862 0.90675 0.90018 0.89010 1.22078 1.11897 0.94592 1.02756 1.24651 0.94410 1.02942 0.94347 1.86624 1.37738 1.36122 1.72653 0.86071 0.79922 0.78970 0.80294 1.16442 1.16818 1.15920 1.18197 0.77259 0.88639 0.84320 1.90783 1.47178 1.14901 1.78677 1.26477 1.07857 0.98000 1.15621 0.91009 0.91128 0.91151 0.91102 0.91141 0.91055 0.90437 0.90423 0.91390 0.91216 0.90407 0.90714 0.87059 0.88849 0.88863 0.82050 0.82614 0.78748 0.85780 0.78034 0.89474 0.89740 Number of geometries 1 Number of calculations of the screened coulomb radii 1 The total number of SCF iterations 14. Note: The number of geometries may not correspond to the number of cycles due to rejected geometry changes. In the following table subtotal= G_P + SS G_CDS. Atom Chem. CM2 G_P Area Sigma k SS G_CDS Subtotal M number symbol chg. (kcal) (Ang**2) cal/(Ang**2) (kcal) (kcal) value 1 C -0.45 1.28 8.65 101.05 0.87 2.15 16 2 Si 1.00 -3.78 11.60 -169.99 -1.97 -5.75 16 3 C -0.45 1.01 8.65 101.05 0.87 1.89 16 4 C -0.41 1.30 4.98 37.53 0.19 1.49 16 5 C -0.11 0.33 5.61 -26.60 -0.15 0.18 16 6 C -0.12 0.33 4.80 -27.22 -0.13 0.20 16 7 C -0.06 0.12 2.32 -91.65 -0.21 -0.09 16 8 C 0.47 0.26 7.24 36.01 0.26 0.52 16 9 O -0.50 -1.76 15.76 -18.76 -0.30 -2.05 16 10 O -0.36 0.14 8.26 -39.26 -0.32 -0.19 16 11 C 0.12 -0.08 5.38 36.00 0.19 0.11 16 12 C -0.10 0.04 5.89 -104.50 -0.62 -0.57 16 13 C -0.01 0.01 9.10 -39.51 -0.36 -0.35 16 14 C -0.12 -0.05 6.22 -39.50 -0.25 -0.29 16 15 Br -0.02 -0.01 33.69 -68.01 -2.29 -2.30 16 16 C 0.00 0.00 9.40 -39.30 -0.37 -0.37 16 17 C -0.21 -0.33 5.89 -104.84 -0.62 -0.95 16 18 C 0.16 0.03 6.74 -38.49 -0.26 -0.22 16 19 O -0.21 0.21 9.21 5.66 0.05 0.26 16 20 C 0.13 -0.26 9.99 29.43 0.29 0.03 16 21 C -0.31 -0.03 5.32 -104.49 -0.56 -0.59 16 22 C -0.05 0.02 2.46 36.01 0.09 0.11 16 23 O -0.53 -0.49 12.88 -35.23 -0.45 -0.95 16 24 Si 0.93 -2.31 25.30 -169.99 -4.30 -6.61 16 25 H -0.24 0.59 7.11 56.52 0.40 0.99 16 26 H -0.24 0.87 6.91 56.52 0.39 1.26 16 27 H -0.24 0.16 7.11 56.52 0.40 0.56 16 28 C 0.43 1.24 6.98 -34.34 -0.24 1.00 16 29 O -0.44 -2.66 16.93 4.99 0.08 -2.57 16 30 C -0.40 0.77 3.53 37.53 0.13 0.90 16 31 H 0.07 -0.19 7.96 -51.93 -0.41 -0.60 16 32 H 0.07 -0.18 7.96 -51.93 -0.41 -0.59 16 33 H 0.07 -0.22 7.96 -51.93 -0.41 -0.63 16 34 H 0.07 -0.15 7.96 -51.93 -0.41 -0.56 16 35 H 0.07 -0.14 7.96 -51.93 -0.41 -0.55 16 36 H 0.07 -0.16 7.96 -51.93 -0.41 -0.57 16 37 H 0.08 -0.25 7.99 -51.93 -0.41 -0.66 16 38 H 0.08 -0.23 7.99 -51.93 -0.41 -0.64 16 39 H 0.07 -0.26 7.69 -51.93 -0.40 -0.66 16 40 H 0.07 -0.20 8.14 -51.93 -0.42 -0.62 16 41 H 0.08 -0.22 7.66 -51.93 -0.40 -0.61 16 42 H 0.07 -0.18 7.90 -51.93 -0.41 -0.59 16 43 H 0.11 -0.41 7.69 -51.93 -0.40 -0.81 16 44 H 0.09 -0.08 8.13 -51.93 -0.42 -0.51 16 45 H 0.09 -0.09 8.13 -51.93 -0.42 -0.51 16 46 H 0.16 -0.28 6.96 -52.48 -0.37 -0.65 16 47 H 0.16 0.20 7.81 -52.48 -0.41 -0.21 16 48 H 0.20 -0.96 4.64 -52.49 -0.24 -1.21 16 49 H 0.12 0.01 7.96 -51.93 -0.41 -0.40 16 50 H 0.37 -1.17 8.70 45.56 0.40 -0.77 16 51 H 0.09 -0.10 7.95 -51.93 -0.41 -0.51 16 52 H 0.08 -0.11 7.98 -51.93 -0.41 -0.52 16 LS Contribution 445.00 15.07 6.71 6.71 Total: 0.00 -8.39 445.00 -10.50 -18.89 By element: Atomic # 1 Polarization: -3.73 SS G_CDS: -6.85 Total: -10.58 kcal Atomic # 6 Polarization: 6.00 SS G_CDS: -0.85 Total: 5.15 kcal Atomic # 8 Polarization: -4.56 SS G_CDS: -0.94 Total: -5.50 kcal Atomic # 14 Polarization: -6.09 SS G_CDS: -6.27 Total: -12.36 kcal Atomic # 35 Polarization: -0.01 SS G_CDS: -2.29 Total: -2.30 kcal Total LS contribution 6.71 Total: 6.71 kcal Total: -8.39 -10.50 -18.89 kcal The number of atoms in the molecule is 52 The average number of expansion shells was 16.00 The maximum number of expansion shells was 16 The minimum number of expansion shells was 16 **** NOTA BENE **** This is the net solvation energy for this exact molecular structure (nuclear and electronic)! The standard-state solvation energy should be obtained as the difference between the heat of formation plus delta-G solvation for the relaxed solvated system and that for the relaxed gas-phase system. s_1458_17845584_484008.mol2 52 1SCF run This is a breakdown of the solvation energy calculated without geometric relaxation in solution: (1) E-EN(sol) electronic-nuclear energy of solute -160.553 kcal (2) G-P(sol) polarization free energy of solvation -8.388 kcal (3) G-ENP(sol) elect.-nuc.-pol. free energy of system -168.941 kcal (4) G-CDS(sol) cavity-dispersion-solvent structure free energy -10.497 kcal (5) G-P-CDS(sol) = G-P(sol) + G-CDS(sol) = (2) + (4) -18.885 kcal (6) G-S(sol) free energy of system = (1) + (5) -179.439 kcal 1SCF WAS SPECIFIED, SO GEOMETRY OPTIMIZATION WAS NOT USED Total computer time = 1.44 seconds