Structural and vibrational analysis of Ethyl methanesulfonate, CH3SO2OCH2CH3.

M. E. TUTTOLOMONDO; A. NAVARRO; T. PEÑA; E. L. VARETTI; A. BEN ALTABEF

JOURNAL OF PHYSICAL CHEMISTRY A

American Chemical Society

Año: 2005 vol. 109 p. 7946 - 7956

1089-5639

Ethyl methanesulfonate, CH3SO2OCH2CH3, is well-known as an alkylating agent in mutagenic and carcinogenic processes. Its electronic structure and that of the methanesulfonate anion (CH3SO3 processes. Its electronic structure and that of the methanesulfonate anion (CH3SO3 3SO2OCH2CH3, is well-known as an alkylating agent in mutagenic and carcinogenic processes. Its electronic structure and that of the methanesulfonate anion (CH3SO33SO3 -) were determined using optimization methods based on density functional theory and Moller-Plesset second-order perturbation theory. For CH3SO2OCH2CH3, two conformations with symmetries Cs and C1 are obtained, the former being more stable than the latter. Natural bond orbital (NBO) calculations show the Cs conformation provides a more favorable geometry of the lone pairs of the oxygen atom linking the ethyl group. The NBO technique also reveals the characteristics of the methanesulfonate anion as a leaving group due to the rearrangement of the excess electronic charge after alkylation. Furthermore, the infrared spectra of CH3SO2OCH2CH3 are reported for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. favorable geometry of the lone pairs of the oxygen atom linking the ethyl group. The NBO technique also reveals the characteristics of the methanesulfonate anion as a leaving group due to the rearrangement of the excess electronic charge after alkylation. Furthermore, the infrared spectra of CH3SO2OCH2CH3 are reported for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. stable than the latter. Natural bond orbital (NBO) calculations show the Cs conformation provides a more favorable geometry of the lone pairs of the oxygen atom linking the ethyl group. The NBO technique also reveals the characteristics of the methanesulfonate anion as a leaving group due to the rearrangement of the excess electronic charge after alkylation. Furthermore, the infrared spectra of CH3SO2OCH2CH3 are reported for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. favorable geometry of the lone pairs of the oxygen atom linking the ethyl group. The NBO technique also reveals the characteristics of the methanesulfonate anion as a leaving group due to the rearrangement of the excess electronic charge after alkylation. Furthermore, the infrared spectra of CH3SO2OCH2CH3 are reported for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. For CH3SO2OCH2CH3, two conformations with symmetries Cs and C1 are obtained, the former being more stable than the latter. Natural bond orbital (NBO) calculations show the Cs conformation provides a more favorable geometry of the lone pairs of the oxygen atom linking the ethyl group. The NBO technique also reveals the characteristics of the methanesulfonate anion as a leaving group due to the rearrangement of the excess electronic charge after alkylation. Furthermore, the infrared spectra of CH3SO2OCH2CH3 are reported for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. favorable geometry of the lone pairs of the oxygen atom linking the ethyl group. The NBO technique also reveals the characteristics of the methanesulfonate anion as a leaving group due to the rearrangement of the excess electronic charge after alkylation. Furthermore, the infrared spectra of CH3SO2OCH2CH3 are reported for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. stable than the latter. Natural bond orbital (NBO) calculations show the Cs conformation provides a more favorable geometry of the lone pairs of the oxygen atom linking the ethyl group. The NBO technique also reveals the characteristics of the methanesulfonate anion as a leaving group due to the rearrangement of the excess electronic charge after alkylation. Furthermore, the infrared spectra of CH3SO2OCH2CH3 are reported for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. favorable geometry of the lone pairs of the oxygen atom linking the ethyl group. The NBO technique also reveals the characteristics of the methanesulfonate anion as a leaving group due to the rearrangement of the excess electronic charge after alkylation. Furthermore, the infrared spectra of CH3SO2OCH2CH3 are reported for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. optimization methods based on density functional theory and Moller-Plesset second-order perturbation theory. For CH3SO2OCH2CH3, two conformations with symmetries Cs and C1 are obtained, the former being more stable than the latter. Natural bond orbital (NBO) calculations show the Cs conformation provides a more favorable geometry of the lone pairs of the oxygen atom linking the ethyl group. The NBO technique also reveals the characteristics of the methanesulfonate anion as a leaving group due to the rearrangement of the excess electronic charge after alkylation. Furthermore, the infrared spectra of CH3SO2OCH2CH3 are reported for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. favorable geometry of the lone pairs of the oxygen atom linking the ethyl group. The NBO technique also reveals the characteristics of the methanesulfonate anion as a leaving group due to the rearrangement of the excess electronic charge after alkylation. Furthermore, the infrared spectra of CH3SO2OCH2CH3 are reported for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. stable than the latter. Natural bond orbital (NBO) calculations show the Cs conformation provides a more favorable geometry of the lone pairs of the oxygen atom linking the ethyl group. The NBO technique also reveals the characteristics of the methanesulfonate anion as a leaving group due to the rearrangement of the excess electronic charge after alkylation. Furthermore, the infrared spectra of CH3SO2OCH2CH3 are reported for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. favorable geometry of the lone pairs of the oxygen atom linking the ethyl group. The NBO technique also reveals the characteristics of the methanesulfonate anion as a leaving group due to the rearrangement of the excess electronic charge after alkylation. Furthermore, the infrared spectra of CH3SO2OCH2CH3 are reported for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. For CH3SO2OCH2CH3, two conformations with symmetries Cs and C1 are obtained, the former being more stable than the latter. Natural bond orbital (NBO) calculations show the Cs conformation provides a more favorable geometry of the lone pairs of the oxygen atom linking the ethyl group. The NBO technique also reveals the characteristics of the methanesulfonate anion as a leaving group due to the rearrangement of the excess electronic charge after alkylation. Furthermore, the infrared spectra of CH3SO2OCH2CH3 are reported for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. favorable geometry of the lone pairs of the oxygen atom linking the ethyl group. The NBO technique also reveals the characteristics of the methanesulfonate anion as a leaving group due to the rearrangement of the excess electronic charge after alkylation. Furthermore, the infrared spectra of CH3SO2OCH2CH3 are reported for the liquid and solid states as well as the Raman spectrum of the liquid. Comparison to experiment of the conformationally averaged IR spectrum of Cs and C1 provides evidence of the predicted conformations in the solid IR spectrum. These experimental data along with the calculated theoretical force constants are used to define a scaled quantum mechanical force field for the target molecule, which allowed the measured frequencies to be reproduced with a final root-mean-square deviation of 9 cm-1 and, thus, a reliable assignment of the vibrational spectrum. vibrational spectrum. solid IR spectrum. These experimental data along with the calculated theoretical force con