Mode Computed Frequencies Observed Freq. PEDs Mode Assignment
Unscaled Scaled Raman IR
ν1 3835(75,134)0.23 3662 - 3430# ν(O23-H24)(100) ν(O23-H24)
ν2 3576(24,51)0.75 3415 - - νasym(NH2)(100) νasym(NH2)
ν3 3507(12,94)0.13 3349 - - νsym(NH2)(90)-ν(O21-H22)(10) νsym(NH2)
ν4 3481(251,115)0.07 3324 3207# 3207 ν(O21-H22)(89)+ ν(N16-H18)(7) ν(O21-H22)
ν5 3194(4,144)0.22 3050 3061# 3041, 3068# ν(C6-H10)(94) ν(CH)
ν6 3166(9,135)0.16 3024 3042# 3025, 3042# ν(C3-H8)(65)+ ν(C2-H7)(33) ν(CH)
ν7 3160(8,48)0.51 3018 3027# 3024# ν(C5-H9)(92) ν(CH)
ν8 3149(16,64)0.61 3007 3014# 3014# ν(C2-H7)(66)-ν(C3-H8)(33) ν(CH)
ν9 3090(6,50)0.41 2951 2950# 2960, 2962# νasym(CH2)(98) νasym(CH2)
ν10 3043(23,25)0.21 2906 2923# 2931, 2928# νsym(CH2)(60)- ν(C12-H15)(39) νsym(CH2)
ν11 3032(5,116)0.10 2896 2863# 2894, 2864# ν(C12-H15)(59)+ νsym(CH2)(40) ν(C12-H15)
ν12 1835(374,15)0.27 1752 - 1630# ν(C19-O20)(78) ν(C19-O20)
ν13 1663(29,5)0.74 1588 1587, 1590# 1582, 1589# d(NH2)(95) d(NH2)
ν14 1653(49,56)0.52 1579 1567 1579 ν(C5-C6)(20)+ ν(C2-C3)(18)-ν(C1-C6)(10)-ν(C3-C4)(10)+ α2(R)(11)+β(C3-H8)(6) ν(R)
ν15 1629(15,5)0.72 1556 1551, 1531# 1572, 1532# ν(C1-C2)(24)+ ν(C4-C5)(17)-ν(C1-C6)(16)-ν(C3-C4)(10)- α3(R)(8) ν(R)
ν16 1543(105,2)0.70 1474 1481, 1463# 1453, 1454# ν(C1-C6)(10)-ν(C3-C4)(10)+ν(C1-C2)(9)-ν(C4-C5)(7)-β(C6-H10)(10)+β(C2-H7)(14)+β(C3-H8)(12)-β(C5-H9)(13)-ν(C1-O23)(8) β(CH)
ν17 1489(6,6)0.73 1422 1419, 1414# 1435, 1438# d(CH2)(89) d(CH2)
ν18 1466(13,0)0.75 1400 - 1417, 1416# ν(C5-C6)(17)+ν(C2-C3)(16)+ν(C4-C5)(6)+β(C6-H10)(12)+β(C2-H7)(9)-β(C3-H8)(7)- α(C1-O23-H24)(8) ν(R)
ν19 1412(433,6)0.61 1348 1365, 1368# 1363, 1367# α(C19-O21-H22)(65)- ν(C1-C6)(15) α(C19-O21-H22)
ν20 1376(14,21)0.40 1314 1327, 1328# 1332, 1328# α(C11-C12-H15) (23)- w(CH2)(23)- r(CH2)(11)- ν(C11-C12)(6) α(C11-C12-H15)
ν21 1361(30,1)0.58 1300 - - β(C5-H9)(11)+β(C3-H8)(10)- α(C1-O23-H24)(11)- α(N16-C12-H15)(10)+ ν(C2-C3)(9)-ν(C1-C2)(8)-ν(C5-C6)(7)-ν(C3-C4)(6) ν(C3-C4)(6)+ν(C1-C6)(6)+ w(CH2)(6) β(CH)
ν22 1358(19,9)0.32 1297 - 1286# α(N16-C12-H15) (27)- w(CH2)(25)+ β(C5-H9)(7) α(N16-C12-H15)
ν23 1344(3,4)0.46 1284 1284, 1286# 1267 α(C11-C12-H15)(14)+ ν(C3-C4)(9)-ν(C4-C5)(8)+ν(C5-C6)(5)+ β(C2-H7)(8)+ β(C6-H10)(8) + α(N16-C12-H15) (8)+ r(CH2)(6) ν(R)
ν24 1292(4,1)0.67 1234 - 1247, 1246# w(CH2)(22)+ r(NH2) (21)+ α(N16-C12-H15) (12)+ α(C11-C12-H15) (11) w(CH2)
ν25 1288(4,14)0.25 1230 1249, 1247# 1243 α(N16-C12-H15) (24)- r(CH2)(16)+ α(C11-C12-H15)(14)- r(NH2)(11) r(CH2)
ν26 1280(115,12)0.03 1222 1214, 1212# 1214, 1213#  ν(C1-O23)(47)- α1(R)(9)-ν(C2-C3)(8)+ β(C2-H7)(8) ν(C1-O23)
ν27 1225(2,27)0.09 1170 1164, 1178# 1176, 1177# ν(C4-C11)(39)- α1(R)(13)- ν(C2-C3)(6)-ν(C3-C4)(6)-ν(C4-C5)(6) ν(R)
ν28 1210(18,7)0.73 1156 1156, 1150# 1155, 1153# ν(C19-O21)(33)- ν(C12-C19)(16)+ r(CH2)(13)+α(C19-O21-H22)(8)- d(COOH)(6)+ r(COOH) (6)+ w(NH2)(6) ν(C19-O21)
ν29 1195(3,4)0.31 1141 - - β(C2-H7)(26)- β(C3-H8)(18)-β(C6-H10)(17)- β(C5-H9)(16)+ ν(C2-C3)(7) β(CH)
ν30 1187(207,12)0.11 1134 1114, 1113# 1113, 1112# α(C1-O23-H24)(48)+ ν(C1-C6)(15)+ β(C6-H10)(8)- ν(C1-O23)(7)- ν(C1-C2)(6) α(C-OH)/OH
ν31 1160(10,3)0.44 1108 1100, 1098# - r(NH2)(19)- r(CH2)(18)- α(C11-C12-H15) (17)+ ν(C19-O21)(6) r(NH2)
ν32 1120(20,1)0.66 1070 - 1099, 1099# β(C6-H10)(12)- β(C5-H9)(10)+ β(C2-H7)(9)- β(C3-H8)(7)+ ν(C2-C3)(10)- ν(C5-C6)(9)+ ν(C12-N16)(8) β(CH)
ν33 1097(14,12)0.54 1048 1045, 1046# 1042, 1046# ν(C12-N16)(39)- ν(C11-C12)(15)+ r(CH2)(7)- β(C12-C19)(6) ν(C11-C12)
ν34 1029(0,0)0.04 983 - - α1(R)(49)+ ν(C1-C6)(11)+ ν(C1-C2)(10)- ν(C3-C4)(7)- ν(C4-C5)(7) α1(R)
ν35 979(48,6)0.29 958 986, 985# 986, 988# τ(CH2)(15)- γ(C5-H9)(14)+ w(NH2) (10)+ γ(C6-H10)(8)- r(NH2)(6)- w(NH2)(6) τ(CH2)
ν36 973(15,2)0.35 952 967# 939, 939# γ(C5-H9)(37)- γ(C6-H10)(26)+ τ(CH2)(6) γ(CH)
ν37 948(48,2)0.57 928 935, 938# 929# w(NH2) (24)- ν(C11-C12)(23)+ γ(C3-H8)(14)+ ν(C12-C19)(7) ν(C12-C19)
ν38 942(7,1)0.74 922 894, 897# - γ(C3-H8)(43)- γ(C2-H7)(16)- Φ1(R)(13) γ(CH)
ν39 887(22,16)0.02 868 878 896, 899# γ(C6-H10)(10)+ α(C4-C11-C12)(10)+ w(NH2) (10)+ γ(C2-H7)(9)+ w(COOH)(7)- γ(C4-C11)(6) w(NH2)
ν40 874(46,1)0.52 855 855# 878, 878# τ(C19-O21)(33)+ τ(CH2)(13)- ν(C12-N16)(13)- w(NH2) (10)- ν(C11-C12)(8) ν(C12-N16)
ν41 855(51,12)0.14 837 845, 846# 842, 842# τ(C19-O21)(36)+ w(NH2)(9)- τ(CH2)(7)- α2(R)(7)+ ν(C12-N16)(6) τ(C19-O21)
ν42 846(20,11)0.04 828 828, 829# 829, 830# w(NH2) (21)+ τ(C19-O21)(13)- ν(C12-C19)(10)+ α3(R)(8)+ ν(C1-O23)(7)+ ν(C1-C6)(6) ν(R)
ν43 837(29,2)0.09 819 808 803, 808# γ(C6-H10)(40)+γ(C5-H9)(28)- γ(C1-O23)(8) γ(CH)
ν44 815(25,1)0.17 798 796, 797# 793, 799# γ(C2-H7)(56)+γ(C3-H8)(22)- γ(C1-O23)(7) γ(CH)
ν45 792(14,8)0.09 775 741, 738# 741, 739# α1(R)(17)-ν(C12-C19)(12)-ν(C1-O23)(10)- d(COOH)(10) + ν(C4-C11)(9)+ w(COOH) (8)- ν(C19-O21)(6) w(COOH)
ν46 730(2,2)0.72 714 - - Φ1(R)(60)+γ(C4-C11)(12)-γ(C1-O23)(12)- w(COOH) (6) Φ1(R)
ν47 702(12,6)0.05 687 714, 714# 713, 715# w(COOH) (24)+ Φ1(R)(16)- ν(C4-C11)(10)- d(COOH)(8)- ν(C11-C12)(7)- α1(R)(7) ν(C4-C11)
ν48 657(3,2)0.66 643 - 646# d(COOH)(34)+w(NH2)(22)+Φ1(R)(10)+w(COOH) (10) d(COOH)
ν49 655(1,5)0.75 641 641, 642# 651 α3(R)(79) α3(R)
ν50 565(11,2)0.46 553 574, 574# 576, 575# ρ(COOH)(16)+γ(C1-O23)(11)+w(NH2)(11)+α(C11-C12-N16) (10)- Φ2(R)(8)- α(C4-C11-C12)(6)- α2(R)(6) r(COOH)
ν51 526(14,1)0.33 515 528, 534# 530, 535# γ(C1-O23)(27) + γ(C4-C11)(13)- Φ2(R)(25)+ d(COOH)(7) - ρ(COOH) (7) Φ2(R)
ν52 492(9,3)0.40 481 492, 496# 495, 499# α2(R)(39)+ γ(C1-O23)(11)- Φ2(R)(10) α2(R)
ν53 428(11,0)0.59 419 - 434, 435# β(C1-O23)(46)- α3(R)(16)+ β(C4-C11)(13)+ Φ3(R)(11) β(C1-O23)
ν54 423(3,0)0.35 414 - 408# Φ3(R)(76) Φ3(R)
ν55 409(4,3)0.32 400 380, 386# 388# α(C11-C12-N16) (37)+ w(COOH)(7)- Φ1(R)(6) α(N16-C12-C11)
ν56 347(7,3)0.58 340 338# 340# α(C11-C12-N16) (22)+ Φ1(R)(16)- γ(C4-C11)(10)+ γ(C1-O23)(10) γ(C1-O23)
ν57 340(8,2)0.28 333 336, 331# 327# α(N16-C12-C19) (40)- ρ(COOH) (29) α(N16-C12-C19)
ν58 310(96,1)0.71 303 311, 313# 313# τ(C1-O23)(89) τ(C1-O23)
ν59 307(15,0)0.74 300 -- -- τ(C12-N16)(41)- τ(C19-O21)(20)- β(C4-C11)(13) β(C4-C11)
ν60 296(27,0)0.73 290 - 294# τ(C12-N16)(41)+β(C4-C11)(16)-τ(C19-O21)(8)-β(C12-C19)(7) τ(C12-N16)
ν61 186(0,1)0.13 182 196# - Φ2(R)(24)- α(C11-C12-C19) (16)- α(C4-C11-C12)(14)- ν(C4-C11)(6)- γ(C4-C11)(6)- γ(C12-C19)(6) α(C4-C11-C12)
ν62 169(9,1)0.66 165 167# -- α(C11-C12-C19) (34)+ Φ2(R)(32)+γ(C12-C19)(7)- α(C4-C11-C12)(7) α(C11-C12-C19)
ν63 83(1,1)0.75 81 -- -- τ(C12-C19)(58)- τ(C12-N16)(14)- τ(C19-O21)(10) τ(C12-C19)
ν64 63(1,1)0.71 62 -- -- τ(C12-C19)(31)-γ(C4-C11)(14)-α(C4-C11-C12)(12)-Φ2(R)(9)-τ(C12-N16)(9)+α(C11-C12-C19) (7)-τ(C19-O21)(6) γ(C4-C11)
ν65 46(3,1)0.75 45 -- -- τ(C11-C12)(46)+ τ(C12-C19)(20)- τ(C12-N16)(7) τ(R’’)
ν66 40(1,4)0.75 39 -- -- τ(C4-C11)(57)+ τ(C12-C19)(18)- τ(C12-N16)(9) τ(R’)
The number before the modes are the % potential energy calculated using normal coordinate analysis. The modes contributing with ≤ 5% have been omitted. The abbreviations ν, δ, α(R), Φ1(R), ν(R), β, γ, α(A-B-C), ω, ρ, τ asym and sym have been used for stretching, scissoring, ring planar deformation, ring non-planar deformation, ring stretching, in plane bending, out of plane bending, angle bending, wagging, rocking, torsion, anti-symmetric and symmetric respectively.
Calculated wave numbers up to 1000 cm-1 were scaled by the scale factor 0.9786 and those above 1000 cm-1 by the scale factor 0.9550 for larger wave numbers. Number outside bracket is frequency in cm-1 unit, numbers within the bracket are IR intensity (approximate) and Raman activity (approximate) and number outside bracket is depolarization ratio. The values superscripted with # are taken from literature Ref.-[6]
Table 6: Observed and computed IR and Raman frequencies of the normal modes of vibration, PEDs and assignments for the most stable conformer of L-TYR in isolated molecule.