Data: ipeakexampledata.mat Multiple partly overlapping Lorentian peaks without added background. Illustrates strategies to minimize errors casued by overlap of nearby peaks when using the curve fitting option (N key) in iPeak. load ipeakexampledata.mat ipeak([x;y],0,1.0468,4.9033e-05,7,20,3993.5,1995,0); ActualPeaks = 1 200 3 150 479.07 2 400 9 150 1437.2 3 800 4 150 638.76 4 1000 2 150 319.38 5 1600 2 150 319.38 6 1800 18 150 2874.4 7 2000 14 150 2235.7 8 2400 15 150 2395.3 9 2600 4 150 638.76 10 3000 4 150 638.76 11 3600 7 150 1117.8 12 3800 7 150 1117.8 13 4000 7 150 1117.8 14 4200 3 150 479.07 15 4600 4 150 638.76 16 4800 8 150 1277.5 17 5000 2 150 319.38 18 5200 5 150 798.45 19 5400 4 150 638.76 20 5800 1 150 159.69 21 6200 4 150 638.76 22 7200 7 150 1117.8 23 7400 2 150 319.38 24 7800 7 150 1117.8 ipeak([x;y],0,1.0468,4.9033e-05,7,20,3993.5,1995,0); Lorentzian shape mode (press Shift-G to change) Amplitude Threshold (AmpT) = 0.94214 Slope Threshold (SlopeT) = 5.4481e-05 Smooth Width (SmoothW) = 8 points Fit Width (FitW) = 16 points No baseline correction Peak# Position Height Width Area 1 218.5 4.4098 201.1 1392.3 2 399.04 9.7007 157.2 2394.2 3 800.83 4.8859 164.74 1263.7 4 990.05 2.9613 225.17 1046.9 5 1803.5 20.349 166.62 5322.9 6 1994.6 16.969 180.78 4816.3 7 2400.6 16.442 160.5 4143.1 8 2574.6 6.6136 361.93 3758.1 9 2998.8 4.6592 188.39 1378.1 10 3606 8.4391 180.62 2393.1 11 3800 9.1067 188 2687.9 12 3995.6 8.7402 183 2511.1 13 4187.9 4.622 258.87 1878.5 14 4609.5 5.6022 212.47 1868.7 15 4798.8 9.2374 166.25 2411 16 4985.4 4.1388 257.05 1670.3 17 5200.2 6.2498 176.66 1733.4 18 5395.3 5.0644 178.93 1422.7 19 5805 1.4791 206.7 479.98 20 6200 4.3116 154.79 1047.8 21 7202.1 7.3337 167.11 1924.1 22 7382.1 3.2228 267.67 1354.4 23 7800.1 7.1736 153.09 1724.2 iPeak/findpeaks misses the small peak #5 near 1600, which forms only a shoulder on the much larger peak at 1800. ---------------------------------------------------------------------- Peak near 1000 Position Height Width Area Actual peaks 1000 2 150 319.38 iPeak/findpeaksL: 990.05 2.9613 225.17 1046.9 N key, 2 peak fit Fitting Error 2.1741% Peak# Position Height Width Area 3 795.6 4.4701 168.66 808.27 >> 4 1007.2 2.3033 178.99 431.95 N key, 3 peak fit Fitting Error 1.5237% Peak# Position Height Width Area 3 798.31 4.3693 156.74 697.23 >> 4 1000.6 2.0201 145.52 406.83 5 1841.5 23.684 222.76 3061 Conclusion: ------------------------------------------------------------------------ Peak near 2400 Position Height Width Area Actual: 2400 15 150 2395.3 iPeak/findpeaksL: 2400.6 16.442 160.5 4143.1 N key, 2 peak fit Fitting Error 2.0696% Peak# Position Height Width Area >> 7 2397.1 15.539 170.69 3233.6 8 2608.9 4.1043 167.91 853.69 N key, 3 peak fit Fitting Error 0.95341% Peak# Position Height Width Area 6 1992.5 16.485 169.77 2751.3 >> 7 2399.3 15.054 150.84 3163.6 8 2603.2 4.2392 178.73 970.66 ------------------------------------------------------------------------ Peak near 2600 Position Height Width Area Actual 2600 4 150 638.76 iPeak/findpeaksL: 2574.6 6.6136 361.93 3758.1 N key, 2 peak fit Fitting Error 2.5294% Peak# Position Height Width Area 7 2396.1 15.257 154.55 2773.8 >> 8 2601.4 4.1399 248.18 1210.6 N key, 3 peak fit Fitting Error 1.2864% Peak# Position Height Width Area 6 1990.4 16.486 174.97 2972.4 7 2399.2 15 148.91 3132.7 >> 8 2602.6 4.2299 186.49 1018.7 N key, 5 peak fit Fitting Error 0.44835% Peak# Position Height Width Area 5 1799.8 18.312 150.37 2416.1 6 2000 14.101 151.47 2921.5 7 2399.8 15.047 151.43 3305.5 >> 8 2601 4.092 153.67 903.4 9 3000.6 4.1561 166.18 658 ---------------------------------------------------------------------- Peak near 5000 Position Height Width Area Actual 5000 2 150 319.38 iPeak/findpeaksL: 4985.4 4.1388 257.05 1670.3 N key, 3 peak fit Fitting Error 1.0994% Peak# Position Height Width Area 15 4796.4 8.7693 160.21 980.36 >> 16 4999.3 2.1402 151.97 980.36 17 5203.7 5.6675 163.81 811.48 ------------------------------------------------------------------------ Weak Peak near 5800 Position Height Width Area Actual 5800 1 150 159.69 Peakfit: 5805 1.4791 206.7 479.98 N key, 3 peak fit Fitting Error 1.92% Peak# Position Height Width Area 18 5394.5 4.9493 172.82 740.66 >> 19 5798.6 1.0644 204.44 290.16 20 6200.5 4.1476 159.94 552.45 ------------------------------------------------------------------------ Peak near 7800 Position Height Width Area Actual 7800 7 150 1117.8 iPeak/peakfit: 7800.1 7.1736 153.09 1724.2 N key, 2 peak fit Fitting Error 1.3606% Peak# Position Height Width Area 22 7378.5 3.0566 197.16 535.27 >> 23 7800.3 7.0028 153.02 1395.1