Comparing the energies between Leap's H placement and that of the old Edit program was surprising: ------ Edit: NSTEP ENERGY RMS GMAX NAME NUMBER 1 7.0454E+48 1.9951E+51 9.8963E+52 HZ2 1132 BOND = 175305.3683 ANGLE = 8623.7961 DIHED = 2455.3782 VDWAALS = ************* EEL = 1929598.0410 HBOND = .0000 1-4 VDW = 326451.6205 1-4 EEL = 18863.9383 CONSTRAINT = .0000 Stopping at NSTEP ENERGY RMS GMAX NAME NUMBER 31 2.0616E+26 4.9380E+26 2.0633E+28 HZ2 859 BOND = 175297.8372 ANGLE = 8623.7084 DIHED = 2455.5569 VDWAALS = ************* EEL = 1490083.0280 HBOND = .0000 1-4 VDW = 328114.1905 1-4 EEL = 18863.8736 CONSTRAINT = .0000 unless ntmin=2 is used: NSTEP ENERGY RMS GMAX NAME NUMBER 100 -1.2050E+04 3.1769E+00 1.2974E+02 C 6998 BOND = 229.0605 ANGLE = 1111.5623 DIHED = 3232.3147 VDWAALS = -3940.8063 EEL = -33507.1288 HBOND = .0000 1-4 VDW = 1532.2224 1-4 EEL = 19293.2242 CONSTRAINT = .0000 ------ leap: NSTEP ENERGY RMS GMAX NAME NUMBER 1 1.9394E+04 1.8636E+03 1.2900E+05 HE1 109 BOND = 946.8790 ANGLE = 3569.1250 DIHED = 2339.0414 VDWAALS = 18021.4236 EEL = -33246.7753 HBOND = .0000 1-4 VDW = 7669.2430 1-4 EEL = 20095.1911 CONSTRAINT = .0000 NSTEP ENERGY RMS GMAX NAME NUMBER 100 -1.4180E+04 1.4426E+00 2.8580E+01 C 5155 BOND = 264.7390 ANGLE = 912.4188 DIHED = 2344.3078 VDWAALS = -3964.4410 EEL = -34426.9438 HBOND = .0000 1-4 VDW = 1397.1188 1-4 EEL = 19292.6593 CONSTRAINT = .0000 ---