SPIN MULTIPLICITY ON STRUCTURE AND VIBRATIONAL SPECTRUM OF CYANAMIDE
Keywords:
Vibrational spectra, cyanamide, Density functional theory methodAbstract
Objective: The geometrical optimization, vibrational spectrum of cyanamide in singlet, triplet and quintet state using Density functional Theory method.
Materials and Methods: The methods used here are MP2, MP3, MP4 and DFT method with different exchange and correlation functional (BLYP, B3LYP, B3PW91, PBEPBE, PBE1PBE) and different basis sets viz. 6-311G, 6-311+G, 6-311+G*, 6-311++G*, 6-311++G**, aug-cc-pvdz, aug-cc-pvtz and SDD to know at what level of theory cyanamide has the lowest energy. All the calculations are performed using Gaussian suit of program
Results: Cyanamide shows the lowest energy at B3LYP/aug-cc-pvdz level among different levels used here. The geometrical parameter and vibrational frequencies obtain at this level are in close agreement with the experimental determinations. Out of nine vibrational modes, seven modes in triplet and eight in quintet state are red shifted than those in a singlet state. The only blue shifted mode in quintet is the C-N stretching mode with a blue shifted of 220 cm-1 than that for the singlet.
Conclusion: The geometrical parameter and vibrational frequencies obtain at this level are in close agreement with the experimental determinations. The dipole moment decreases in higher spin state than the singlet
References
2. Tyler Jk, Sheridan J. J Mol Spectroscopy 1972;43:248-261
3. Fletcher WH, Brown FB. J Chem Phys 1963;39:2478-2490
4. Hector R. The Infrared spectra and structure of Cyanamide(Part I), The Infrared spectra of Formamide, N,N-dideuteroformamide and N- methylformamide(Part II), Ph.D. Thesis, California institute of Technology Pasadena, California; 1956.
5. Wagner Jr GD, Wagner ER. J Phys Chem 1960;64:1480-1485
6. Vincent MA, Dykstra CE. J Chem Phys 1980;73:3838-3842
7. Ichikawa K, Hamada Y, Sugawara Y, Tsuboi M, Kato S, Morokuma K. Chem Phys 1982;72:301-312
8. Daoudi A, Pouchan C, Sauvaitre H. Chem Phys Lett 1982;91:477-483
9. Brown RD, Godfrey PD, Kleibomer B. J Mol Spectrosc 1985;114: 257- 273
10. Birk M, Winnewisser M. Chem Phys Lett 1986;123:382-385
11. Birk M, Winnewisser M. J Mol Spectrosc 1993;159:69-78
12. Kwon CH, Lee JH, Kim HL. Bull Korean Chem Soc 2007;28:1485-1488
13. Lee JH, Kang TY, Hwang H, Kwon CH, Kim HL. Bull KoreanChem Soc 2008;29:1685-1688
14. Frisch MJ, Trucks GW, Schlegel HB, Scuseria GE, Robb MA, Cheeseman JR,Montgomery JA Jr, Vreven T, Kudin K N, Burant JC, Millam JM, Iyengar SS, Tomasi J, Barone V, Mennucci B, Cossi M, Scalmani G, Rega N, Petersson GA, Nakatsuji H, Hada M, Ehara M, Toyota K, Fukuda R, Hasegawa J, Ishida M, Nakajima T, Honda Y, Kitao O, Nakai H, Klene M, Li X, Knox E, Hratchian HP, Cross JB, Bakken V, Adamo C, Jaramillo J, Gomperts R, Stratmann RE, Yazyev O, Austin AJ, Cammi R, Pomelli, C, Ochterski JW, Ayala PY, Morokuma K, Voth GA, Salvador P, Dannenberg JJ, Zakrzewski VG, Dapprich S, Daniels AD, Strain MC, Farkas O, Malick DK, Rabuck AD, Raghavachari K, Foresman JB, Ortiz J V, Cui Q, Baboul AG, Clifford S, Cioslowski J, Stefanov BB, Liu G, Liashenko A, Piskorz P, Komaromi I, Martin RL, Fox DJ, Keith T, Al-Laham MA, Peng CY, Nanayakkara A, Challacombe M, Gill PMW, Johnson B, Chen W, Wong MW, Gonzalez C, Pople JA. Gaussian 03. Gaussian Inc., Pittsburgh 2003