Vibrational frequencies (in cm^(-1)) ******** Radicals ******** ct-1-buten-1-yl 142, 251, 264, 538, 592, 776, 804, 839, 902, 1038, 1113, 1118, 1275, 1302, 1388, 1443, 1506, 1526, 1533, 1696, 3016, 3031, 3041, 3055, 3123, 3125, 3260 cc-1-buten-1-yl 141, 259, 265, 510, 616, 784, 836, 883, 898, 1036, 1099, 1107, 1278, 1301, 1380, 1442, 1504, 1528, 1536, 1688, 3020, 3045, 3053, 3101, 3120, 3122, 3260 tc-1-buten-1-yl 107, 239, 328, 397, 675, 790, 841, 886, 917, 1026, 1094, 1136, 1277, 1308, 1359, 1437, 1510, 1527, 1535, 1687, 3029, 3048, 3081, 3103, 3115, 3123, 3246 tt-1-buten-1-yl 111, 237, 331, 420, 655, 782, 801, 828, 920, 1030, 1100, 1150, 1270, 1309, 1365, 1435, 1512, 1527, 1536, 1696, 3023, 3030, 3047, 3090, 3115, 3124, 3257 cis-2-buten-2-yl 127, 167, 196, 363, 528, 717, 848, 997, 1033, 1055, 1068, 1110, 1332, 1417, 1434, 1490, 1504, 1512, 1521, 1782, 2983, 3035, 3063, 3085, 3088, 3105, 3130 trans-2-buten-2-yl 155, 195, 211, 248, 461, 736, 849, 998, 1056, 1072, 1079, 1127, 1310, 1426, 1432, 1488, 1506, 1514, 1520, 1789, 2982, 3017, 3035, 3065, 3081, 3089, 3134 cis-1-buten-2-yl 142, 194, 253, 467, 489, 800, 846, 877, 979, 1018, 1093, 1113, 1295, 1354, 1421, 1446, 1501, 1523, 1535, 1759, 3026, 3051, 3054, 3063, 3125, 3131, 3169 trans-1-buten-2-yl 108, 217, 286, 366, 555, 788, 841, 881, 970, 1029, 1100, 1140, 1288, 1351, 1435, 1446, 1488, 1526, 1535, 1761, 2963, 3043, 3057, 3057, 3128, 3131, 3171 cis-1-methylallyl 64, 292, 294, 540, 574, 694, 770, 885, 993, 1031, 1039, 1095, 1213, 1258, 1423, 1458, 1479, 1506, 1541, 1552, 3022, 3058, 3133, 3145, 3173, 3179, 3263 trans-1-methylallyl 155, 218, 286, 505, 546, 737, 777, 890, 1001, 1002, 1038, 1151, 1223, 1297, 1358, 1440, 1501, 1504, 1536, 1548, 3014, 3050, 3110, 3136, 3166, 3168, 3259 cis-3-buten-1-yl 151, 163, 282, 473, 538, 589, 832, 886, 940, 1034, 1040, 1063, 1137, 1237, 1340, 1378, 1459, 1484, 1493, 1732, 2920, 3019, 3145, 3166, 3173, 3243, 3271 trans-3-buten-1-yl 102, 136, 323, 419, 471, 657, 804, 905, 940, 1034, 1056, 1084, 1125, 1254, 1331, 1354, 1469, 1484, 1491, 1729, 2956, 3027, 3148, 3157, 3167, 3234, 3269 ******** Conformational Transition States ******** 1-buten-1-yl Conformations ct to cc (CCH bend) 741i, 134, 253, 261, 571, 631, 680, 837, 848, 1030, 1086, 1109, 1274, 1299, 1381, 1441, 1504, 1525, 1533, 1688, 2995, 3021, 3042, 3053, 3121, 3122, 3459 tc to tt (CCH bend) 752i, 101, 237, 340, 437, 637, 765, 813, 875, 1023, 1095, 1106, 1277, 1312, 1355, 1435, 1510, 1527, 1535, 1688, 2993, 3028, 3046, 3091, 3114, 3122, 3459 ct to tt (CCCC rot.) 145i, 248, 282, 466, 645, 775, 801, 806, 911, 1046, 1097, 1132, 1279, 1305, 1371, 1436, 1519, 1526, 1536, 1686, 3030, 3046, 3050, 3084, 3118, 3128, 3260 cc to tc (CCCC rot.) 130i, 245, 279, 451, 672, 779, 831, 870, 905, 1035, 1094, 1118, 1287, 1302, 1364, 1438, 1518, 1527, 1535, 1678, 3043, 3051, 3078, 3110, 3118, 3126, 3251 tc to tc (CCCC rot.) 122i, 250, 284, 433, 616, 784, 823, 872, 924, 1043, 1104, 1116, 1283, 1301, 1361, 1440, 1510, 1528, 1535, 1676, 3043, 3048, 3070, 3099, 3115, 3120, 3248 tt to tt (CCCC rot.) 135i, 246, 283, 463, 584, 755, 777, 823, 935, 1052, 1109, 1131, 1271, 1301, 1368, 1441, 1510, 1529, 1535, 1686, 3022, 3044, 3048, 3070, 3112, 3121, 3260 ct methyl rot. 243i, 157, 267, 559, 586, 784, 803, 887, 895, 1066, 1096, 1112, 1272, 1278, 1376, 1448, 1512, 1532, 1536, 1698, 3022, 3034, 3046, 3062, 3127, 3128, 3263 cc methyl rot. 261i, 117, 292, 524, 608, 800, 830, 883, 915, 1064, 1078, 1103, 1275, 1276, 1372, 1452, 1512, 1531, 1537, 1691, 3028, 3050, 3068, 3093, 3128, 3135, 3267 tc methyl rot. 243i, 110, 330, 394, 673, 814, 843, 901, 944, 1022, 1092, 1130, 1253, 1300, 1352, 1446, 1514, 1533, 1535, 1686, 3039, 3059, 3088, 3106, 3123, 3129, 3246 tt methyl rot. 254i, 117, 334, 414, 656, 786, 808, 860, 948, 1025, 1097, 1145, 1250, 1298, 1357, 1448, 1515, 1533, 1537, 1696, 3025, 3040, 3059, 3099, 3122, 3129, 3257 2-buten-2-yl conformations cis to trans (CCC bend) 259i, 43, 159, 318, 379, 710, 796, 1003, 1020, 1053, 1065, 1068, 1335, 1420, 1442, 1486, 1503, 1513, 1519, 1864, 2972, 2989, 3001, 3032, 3071, 3082, 3132 cis methyl rot. on 1-carbon 137i, 148, 175, 380, 541, 739, 848, 990, 1014, 1037, 1055, 1100, 1330, 1418, 1431, 1490, 1506, 1515, 1520, 1779, 3012, 3033, 3070, 3078, 3083, 3105, 3129 cis methyl rot. on 4-carbon 177i, 108, 173, 366, 536, 732, 854, 1017, 1023, 1048, 1064, 1103, 1324, 1418, 1431, 1490, 1502, 1521, 1521, 1773, 2986, 3045, 3063, 3087, 3100, 3114, 3131 trans methyl rot. on 1-carbon 175i, 185, 208, 250, 463, 737, 847, 1005, 1014, 1064, 1070, 1117, 1307, 1426, 1431, 1492, 1509, 1514, 1520, 1787, 3010, 3016, 3034, 3073, 3079, 3080, 3134 trans methyl rot. on 4-carbon 200i, 177, 208, 225, 465, 715, 861, 1017, 1054, 1065, 1075, 1118, 1304, 1427, 1435, 1488, 1507, 1522, 1524, 1781, 2981, 3019, 3050, 3063, 3097, 3104, 3128 1-buten-2-yl conformations cis to trans (CCCC rot.) 134i, 209, 252, 386, 559, 779, 841, 879, 978, 1022, 1078, 1115, 1285, 1352, 1430, 1448, 1503, 1525, 1532, 1757, 3013, 3040, 3051, 3055, 3124, 3133, 3162 trans to trans (CCCC rot.) 130i, 214, 246, 421, 472, 783, 830, 875, 982, 1032, 1081, 1113, 1293, 1341, 1437, 1446, 1487, 1527, 1534, 1763, 3004, 3040, 3052, 3057, 3127, 3131, 3160 cis methyl rot. 249i, 134, 223, 447, 504, 847, 851, 872, 974, 1030, 1086, 1101, 1271, 1349, 1429, 1456, 1502, 1530, 1533, 1764, 3033, 3055, 3058, 3069, 3137, 3141, 3167 trans methyl rot. 242i, 114, 270, 362, 564, 829, 951, 880, 990, 1026, 1099, 1130, 1259, 1341, 1444, 1446, 1491, 1532, 1534, 1759, 2966, 3048, 3056, 3066, 3133, 3139, 3173 cis to trans (CCC bend) 260i, 41, 224, 328, 371, 781, 813, 884, 965, 986, 1063, 1103, 1301, 1344, 1425, 1471, 1485, 1523, 1532, 1844, 2993, 3019, 3035, 3046, 3053, 3124, 3135 1-methylallyl conformations cis to trans (CCCC rot.) 242i, 98, 275, 307, 487, 671, 867, 947, 991, 1009, 1047, 1114, 1143, 1326, 1364, 1430, 1470, 1503, 1516, 1707, 2965, 3056, 3059, 3111, 3156, 3159, 3237 cis methyl rot. 81i, 256, 312, 537, 580, 658, 783, 912, 991, 1021, 1031, 1109, 1203, 1252, 1421, 1455, 1479, 1510, 1521, 1555, 3019, 3058, 3125, 3149, 3175, 3189, 3261 trans methyl rot. 166i, 211, 277, 497, 554, 706, 782, 906, 1001, 1015, 1031, 1137, 1224, 1300, 1352, 1439, 1506, 1512, 1522, 1546, 3017, 3055, 3123, 3132, 3165, 3170, 3258 cis CH2 rot. 418i, 164, 244, 389, 446, 638, 654, 918, 984, 1030, 1034, 1077, 1116, 1274, 1411, 1446, 1479, 1514, 1515, 1723, 3032, 3071, 3076, 3125, 3142, 3154, 3228 trans CH2 rot. 430i, 206, 248, 276, 442, 539, 724, 921, 990, 1038, 1079, 1106, 1119, 1314, 1341, 1440, 1476, 1510, 1522, 1733, 3031, 3057, 3077, 3115, 3143, 3152, 3230 3-buten-1-yl conformations cis to trans (CCCC rot.) 136i, 120, 286, 435, 448, 666, 841, 879, 941, 1015, 1030, 1096, 1111, 1228, 1342, 1364, 1464, 1481, 1498, 1728, 2963, 3001, 3152, 3161, 3167, 3235, 3272 cis to cis CCCC rot. 215i, 137, 309, 401, 543, 549, 836, 910, 929, 1017, 1038, 1044, 1152, 1208, 1347, 1396, 1461, 1480, 1507, 1739, 2948, 2951, 3142, 3170, 3185, 3243, 3285 trans to trans CCCC rot. 129i, 113, 290, 433, 476, 561, 840, 896, 936, 1000, 1027, 1102, 1170, 1200, 1335, 1357, 1472, 1479, 1489, 1728, 2929, 3004, 3147, 3156, 3169, 3234, 3268 cis} CH2 rot. 29i, 155, 257, 451, 559, 606, 804, 873, 938, 1029, 1040, 1097, 1117, 1294, 1324, 1351, 1459, 1489, 1508, 1730, 2999, 3026, 3139, 3164, 3169, 3241, 3267 trans CH2 rot. 139i, 116, 301, 419, 433, 646, 819, 908, 936, 988, 1036, 1074, 1192, 1238, 1329, 1348, 1474, 1485, 1496, 1731, 2936, 3077, 3143, 3157, 3171, 3234, 3273 ******** Isomerization Transition States ******** cis-1-methylallyl to cis-1-methylallyl 1918i, 307, 332, 564, 600, 684, 774, 938, 947, 956, 1049, 1065, 1066, 1111, 1167, 1368, 1392, 1474, 1476, 1636, 1702, 3084, 3086, 3151, 3152, 3166, 3189 cis-3-buten-1-yl to ct-1-buten-1-yl 1843i, 170, 469, 612, 656, 729, 851, 889, 913, 956, 1027, 1081, 1096, 1237, 1261, 1280, 1318, 1481, 1519, 1656, 1702, 3134, 3060, 3119, 3156, 3195, 3232 trans-1-buten-2-yl to trans-3-buten-1-yl 2156i, 88, 335, 359, 596, 625, 795, 883, 892, 957, 1006, 1062, 1122, 1212, 1241, 1263, 1441, 1458, 1503, 1735, 1812, 3058, 3098, 3106, 3126, 3210, 3226 trans-1-methylallyl to tt-1-buten-1-yl 2186i, 193, 222, 366, 636, 674, 826, 863, 896, 959, 1055, 1096, 1121, 1179, 1235, 1354, 1428, 1514, 1518, 1647, 1812, 3013, 3084, 3092, 3123, 3147, 3197 trans-1-methylallyl to trans-2-buten-2-yl, 1,3 H atom migration 2221i, 158, 236, 299, 473, 600, 813, 912, 971, 1046, 1051, 1061, 1080, 1152, 1250, 1420, 1463, 1493, 1508, 1744, 1807, 3018, 3083, 3086, 3097, 3169, 3185 cis-1-buten-2-yl to cis-1-methylallyl 1926i, 168, 188, 383, 497, 516, 767, 804, 875, 1025, 1043, 1087, 1141, 1200, 1394, 1426, 1470, 1509, 1518, 1656, 2136, 3024, 3093, 3098, 3128, 3150, 3203 trans-1-buten-2-yl to trans-1-methylallyl 1932i, 186, 221, 279, 451, 632, 788, 815, 890, 1012, 1038, 1109, 1145, 1161, 1336, 1436, 1468, 1508, 1526, 1661, 2157, 3029, 3064, 3086, 3096, 3122, 3206 cis-2-buten-2-yl to cis-2-buten-2-yl 2197i, 103, 127, 200, 256, 389, 435, 756, 995, 1039, 1055, 1055, 1056, 1411, 1421, 1499, 1500, 1507, 1507, 1943, 2342, 3009, 3015, 3086, 3087, 3106, 3106 cis-1-buten-2-yl to cc-1-buten-1-yl 2195i, 125, 174, 195, 242, 539, 577, 793, 811, 869, 994, 1082, 1104, 1295, 1352, 1429, 1500, 1523, 1533, 1866, 2358, 3041, 3053, 3058, 3069, 3122, 3129 trans-1-buten-2-yl to tc-1-buten-1-yl 2184i, 79, 199, 225, 321, 415, 609, 794, 810, 876, 1019, 1093, 1099, 1289, 1344, 1436, 1494, 1525, 1535, 1871, 2353, 2998, 3050, 3056, 3060, 3126, 3130 trans-1-methylallyl to trans-2-buten-2-yl, 1,2 H atom migration 1995i, 166, 232, 244, 403, 517, 792, 845, 897, 1022, 1064, 1115, 1153, 1163, 1323, 1433, 1478, 1511, 1518, 1716, 2168, 3024, 3059, 3066, 3080, 3127, 3204 cis-1-methylallyl to cis-2-buten-2-yl 2000i, 158, 196, 341, 395, 571, 793, 839, 897, 1037, 1047, 1075, 1111, 1152, 1369, 1427, 1478, 1510, 1520, 1698, 2176, 3020, 3071, 3080, 3118, 3146, 3205 trans-1-methylallyl to trans-3-buten-1-yl 1903i, 169, 278, 382, 493, 606, 637, 830, 853, 877, 989, 999, 1154, 1242, 1264, 1318, 1370, 1454, 1498, 1650, 2191, 3137, 3164, 3174, 3190, 3249, 3306 cis-1-methylallyl to cis-3-buten-1-yl 1889i, 203, 278, 418, 560, 620, 625, 830, 846, 878, 983, 1034, 1088, 1207, 1281, 1333, 1425, 1476, 1482, 1638, 2201, 3156, 3170, 3182, 3199, 3250, 3310 ******** Dissociation Transition States ******** cc-1-buten-1-yl to ethyl + acetylene 429i, 42, 143, 149, 281, 474, 530, 606, 717, 774, 802, 832, 1025, 1080, 1229, 1427, 1497, 1513, 1515, 1935, 2996, 3075, 3114, 3139, 3228, 3402, 3490 tc-1-buten-1-yl to ethyl + acetylene 434i, 24, 152, 157, 245, 497, 533, 605, 740, 774, 805, 827, 1024, 1073, 1226, 1430, 1496, 1514, 1517, 1933, 2987, 3058, 3102, 3153, 3245, 3396, 3487 ct-1-buten-1-yl to 1-butyne + H 601i, 122, 232, 240, 372, 452, 538, 621, 628, 797, 853, 1022, 1097, 1126, 1302, 1364, 1434, 1507, 1523, 1534, 2148, 3051, 3060, 3079, 3131, 3139, 3486 tt-1-buten-1-yl to 1-butyne + H 614i, 129, 234, 256, 428, 476, 523, 625, 632, 799, 849, 1029, 1100, 1121, 1303, 1369, 1437, 1505, 1525, 1536, 2147, 3047, 3061, 3081, 3133, 3139, 3485 cis-2-buten-2-yl to propyne + methyl 420i, 38, 61, 113, 339, 353, 438, 466, 628, 714, 807, 945, 1055, 1076, 1441, 1444, 1449, 1504, 1505, 2116, 3027, 3082, 3099, 3125, 3279, 3289, 3438 trans-2-buten-2-yl to 2-butyne + H 526i, 69, 148, 191, 216, 396, 412, 507, 736, 1053, 1067, 1068, 1081, 1175, 1440, 1444, 1504, 1507, 1507, 1512, 2297, 3034, 3047, 3091, 3100, 3112, 3113 cis-2-buten-2-yl to 1,2-butadiene + H 254i, 162, 168, 206, 274, 357, 579, 591, 884, 888, 901, 1040, 1071, 1102, 1155, 1377, 1432, 1498, 1513, 1529, 2051, 3041, 3092, 3127, 3146, 3147, 3216 trans-2-buten-2-yl to 1,2-butadiene + H 250i, 170, 171, 180, 258, 372, 580, 584, 880, 889, 903, 1041, 1071, 1100, 1156, 1378, 1435, 1498, 1514, 1530, 2053, 3041, 3092, 3125, 3144, 3146, 3216 cis-1-buten-2-yl to allene + methyl 416i, 96, 123, 338, 346, 380, 500, 518, 786, 870, 872, 897, 1018, 1062, 1072, 1448, 1451, 1459, 1499, 1979, 3112, 3121, 3148, 3175, 3221, 3273, 3284 cis-1-buten-2-yl to 1-butyne + H 402i, 12, 169, 223, 311, 368, 532, 602, 728, 800, 856, 1023, 1097, 1124, 1302, 1365, 1436, 1507, 1524, 1534, 2193, 3036, 3063, 3065, 3135, 3143, 3487 trans-1-buten-2-yl to 1-butyne + H 393i, 37, 191, 215, 266, 401, 526, 613, 723, 795, 853, 1029, 1100, 1120, 1300, 1368, 1438, 1502, 1526, 1535, 2195, 3032, 3062, 3062, 3133, 3139, 3487 trans-1-buten-2-yl to 1,2-butadiene + H 531i, 169, 209, 253, 389, 446, 549, 582, 871, 883, 934, 1022, 1068, 1106, 1151, 1379, 1435, 1490, 1517, 1528, 2026, 3049, 3112, 3130, 3140, 3153, 3197 cis-1-methylallyl to 1,2-butadiene + H 673i, 87, 173, 256, 351, 504, 516, 596, 852, 885, 892, 1040, 1070, 1105, 1148, 1379, 1431, 1496, 1513, 1526, 2003, 3040, 3090, 3139, 3142, 3178, 3215 trans}-1-methylallyl to 1,2-butadiene + H 634i, 28, 161, 314, 358, 493, 550, 562, 852, 875, 884, 1039, 1077, 1095, 1171, 1378, 1433, 1496, 1511, 1525, 2003, 3040, 3090, 3120, 3141, 3142, 3215 cis-1-methylallyl to cis-1,3-butadiene + H (HF frequencies) 236i, 112, 189, 257, 316, 541, 607, 709, 896, 901, 948, 989, 1033, 1135, 1177, 1292, 1338, 1555, 1558, 1654, 1696, 3326, 3336, 3340, 3352, 3421, 3430 trans-1-methylallyl to trans-1,3-butadiene + H (HF frequencies) 316i, 173, 208, 291, 318, 539, 584, 749, 911, 916, 959, 987, 1057, 1078, 1257, 1344, 1359, 1477, 1592, 1656, 1671, 3323, 3332, 3336, 3339, 3418, 3426 cis-3-buten-1-yl to vinyl + ethylene 251i, 47, 122, 241, 242, 358, 781, 831, 856, 883, 926, 939, 1032, 1099, 1248, 1348, 1412, 1489, 1635, 1674, 3088, 3159, 3170, 3176, 3221, 3232, 3258 trans-3-buten-1-yl to vinyl + ethylene 253i, 17, 133, 202, 232, 337, 785, 831, 863, 881, 927, 936, 1032, 1098, 1278, 1343, 1420, 1491, 1630, 1668, 3079, 3160, 3164, 3172, 3233, 3241, 3260 cis-3-buten-1-yl to cis-1,3-butadiene + H 584i, 140, 279, 354, 380, 503, 610, 738, 886, 907, 938, 1025, 1035, 1076, 1111, 1310, 1350, 1452, 1482, 1639, 1710, 3154, 3164, 3170, 3175, 3248, 3257 trans-3-buten-1-yl to trans-1,3-butadiene + H 724i, 159, 295, 360, 433, 516, 553, 753, 890, 899, 933, 1007, 1014, 1067, 1231, 1307, 1331, 1422, 1493, 1617, 1715, 3154, 3165, 3167, 3170, 3248, 3257 ******** Branched and Cyclic Isomers ******** 2-methyl-1-propenyl 174, 205, 359, 397, 424, 679, 800, 889, 969, 978, 1106, 1110, 1216, 1420, 1438, 1503, 1510, 1514, 1519, 1713, 3028, 3034, 3079, 3082, 3132, 3142, 3245 2-methylallyl 21, 407, 430, 482, 549, 556, 758, 791, 855, 981, 1037, 1059, 1072, 1352, 1390, 1444, 1510, 1524, 1526, 1558, 3049, 3108, 3129, 3164, 3172, 3255, 3258 cyclobutyl 90, 240, 751, 761, 795, 912, 916, 978, 1010, 1020, 1046, 1199, 1225, 1230, 1260, 1304, 1331, 1489, 1496, 1526, 2994, 2999, 3015, 3019, 3081, 3131, 3204 cyclopropylmethyl 138, 328, 370, 462, 777, 787, 813, 854, 936, 1031, 1057, 1073, 1128, 1214, 1218, 1228, 1401, 1492, 1498, 1524, 3142, 3146, 3162, 3172, 3218, 3234, 3272 1-methylcyclopropyl 161, 245, 324, 715, 756, 845, 925, 937, 1001, 1040, 1078, 1141, 1152, 1173, 1405, 1441, 1483, 1501, 1513, 1529, 2968, 3068, 3092, 3093, 3108, 3154, 3166 2-methylcyclopropyl (conformer 1) 208, 323, 358, 631, 783, 829, 891, 912, 1009, 1048, 1088, 1108, 1139, 1185, 1259, 1403, 1439, 1500, 1521, 1529, 3038, 3095, 3098, 3099, 3114, 3166, 3219 2-methylcyclopropyl (conformer 2) 226, 323, 368, 614, 760, 820, 874, 930, 1019, 1055, 1090, 1102, 1152, 1177, 1253, 1403, 1438, 1499, 1522, 1530, 3042, 3094, 3096, 3104, 3120, 3163, 3225