ABSTRACT
The infrared vibration-rotation bands of SeH have been measured in the X(2)Pi ground state using a Fourier transform spectrometer. The bands were observed in a microwave discharge of a mixture of H(2) and Se in the presence of He. The rotational structure of the 1-0, 2-1, 3-2 bands of the X(2)Pi(3/2) spin component and the 1-0 band of X(2)Pi(1/2) spin component has been observed in the 1800-2600 cm(-1) region. The principal ground state molecular constants obtained are omega(e) = 2421.7153(234) cm(-1), omega(e)x(e) = 44.6012(110) cm(-1), omega(e)y(e) = 0.20697(236) cm(-1), B(e) = 7.899187(696) cm(-1), alpha(e) = 0.220749(399) cm(-1), and r(e) = 1.464319(64) Å. This work is the first determination of the equilibrium molecular constants of the X(2)Pi state of SeH. Copyright 2000 Academic Press.
ABSTRACT
The high-resolution spectrum of NbN has been investigated in emission in the 3000-15 000 cm(-1) region using a Fourier transform spectrometer. The bands were excited in a microwave discharge through a mixture of NbCl(5) vapor, approximately 5 mTorr of N(2), and 3 Torr of He. Numerous bands observed in the near-infrared region have been classified into the following transitions: f(1)Phi-c(1)Gamma, e(1)Pi-a(1)Delta, C(3)Pi(0+)-A(3)Sigma(-)(1), C(3)Pi(0-)-A(3)Sigma(-)(1), C(3)Pi(1)-a(1)Delta, C(3)Pi(1)-A(3)Sigma(-)(0), d(1)Sigma(+)-A(3)Sigma(-)(0), and d(1)Sigma(+)-b(1)Sigma(+). These observations are consistent with the energy level diagram provided by laser excitation and emission spectroscopy [Y. Azuma, G. Huang, M. P. J. Lyne, A. J. Merer, and V. I. Srdanov, J. Chem. Phys. 100, 4138-4155 (1993)]. The missing d(1)Sigma(+) state has been observed for the first time and its spectroscopic parameters are consistent with the theoretical predictions of S. R. Langhoff and W. Bauschlicher, Jr. [J. Mol. Spectrosc. 143, 169-179 (1990)]. Rotational analysis of a number of bands has been obtained and improved spectroscopic parameters have been extracted for the low-lying electronic states. The observation of several vibrational bands with v = 1 has enabled us to determine the vibrational intervals and equilibrium bond lengths for the A(3)Sigma(-)(0), a(1)Delta, b(1)Sigma(+), d(1)Sigma(+), and C(3)Pi(1) states. Copyright 2000 Academic Press.
ABSTRACT
The emission spectrum of IrN was recorded in the near infrared using a Fourier transform spectrometer. The IrN molecules were excited in an Ir hollow cathode lamp operated with a mixture of Ne and a trace of N(2). Numerous IrN bands observed in the 7500-9200 cm(-1) region were assigned to a new a(3)Pi-X(1)Sigma(+) electronic transition with the 0-0 bands of the a(3)Pi(0)-X(1)Sigma(+) and a(3)Pi(1)-X(1)Sigma(+) subbands near 9175 and 8841 cm(-1), respectively. A rotational analysis of several bands of the 0-0 and 0-1 sequences was obtained and molecular constants were extracted. The effective Hund's case (a) constants for the new a(3)Pi state are: T(00) = 8840.31747(88) cm(-1), A(0) = -340.53329(93) cm(-1), DeltaG(1/2) = 984.3629(23) cm(-1), B(e) = 0.4699116(27) cm(-1), alpha(e) = 0.0030058(50) cm(-1), and r(e)= 1.6576432(47) Å. The spectroscopic properties of the ground state and several low-lying electronic states of IrN were also predicted by ab initio calculations. These calculations are consistent with our assignment of the a(3)Pi-X(1)Sigma(+) transition and also support our previous assignments of the A' (1)Pi and A(1)Pi electronic states [R. S. Ram and P. F. Bernath, J. Mol. Spectrosc. 193, 363 (1999)]. The excited a(3)Pi state of IrN has an 1varsigma(2)2varsigma(2)1pi(4)3varsigma(1)1delta(4)2pi(1) electron configuration and the configurations of the other low-lying electronic states are also discussed. Copyright 1999 Academic Press.
ABSTRACT
The emission spectrum of ZrCl has been observed in the 1800-12 000 cm(-1) region using a Fourier transform spectrometer. The molecules were excited in a microwave discharge of a mixture of helium and a trace of ZrCl(4) vapor. In addition to the C(4)Delta-X(4)Phi transition reported previously, numerous new bands observed in the near infrared have been classified into two electronic transitions, [7.3](2)Delta-a(2)Phi and [9.4](2)Phi-a(2)Phi. Five new bands observed in the 6700-7400 cm(-1) region have been assigned as (2)Delta(3/2)-(2)Phi(5/2) and (2)Delta(5/2)-(2)Phi(7/2) subbands of a new electronic transition, [7.3](2)Delta-a(2)Phi. The two subbands of the [9.4](2)Phi-a(2)Phi transition were previously observed by G. Phillips, S. P. Davis, and D. C. Galehouse [Astrophys. J. Suppl. 43, 417-434 (1980)], who tentatively labeled them as (2)Pi(1/2)-(2)Pi(1/2) and (2)Pi(3/2)-(2)Pi(3/2) subbands. A number of new bands involving higher vibrational levels have been identified for these two subbands. A rotational analysis of a number of bands of both transitions has been obtained and spectroscopic constants have been determined. Global perturbations have been observed in both spin components of the a(2)Phi state. The assignment of the observed electronic states has been discussed in light of recent theoretical calculations. Copyright 1999 Academic Press.
ABSTRACT
High-resolution emission spectra of TiCl have been recorded in the 10 000-18 000 cm-1 region using a Fourier transform spectrometer. The molecules were excited in a microwave discharge through a flowing mixture of TiCl4 and helium. TiCl bands observed in the 11 000-13 500 cm-1 region have been assigned to a new [12.8]2Phi-a2Phi electronic transition with the 0-0 bands of 2Phi5/2-2Phi5/2 and 2Phi7/2-2Phi7/2 subbands at 12 733.7 and 12 791.5 cm-1, respectively. A rotational analysis of several bands has been obtained, and spectroscopic constants have been extracted. This assignment is supported by the available theoretical calculations and is also consistent with the near infrared measurements of a doublet-doublet transition of ZrCl [J. G. Phillips, S. P. Davis, and D. C. Galehouse, Astrophys. J. Suppl. Ser. 43, 417-434) (1980)]. Copyright 1999 Academic Press.
ABSTRACT
The emission spectrum of IrN has been investigated in the 10 000-20 000 cm-1 region at 0.02 cm-1 resolution using a Fourier transform spectrometer. The bands were excited in an Ir hollow cathode lamp operated with a mixture of 2 Torr of Ne and a trace of N2. Numerous bands have been classified into two transitions labeled as A1Pi-X1Sigma+ and A' 1Pi-X1Sigma+ by analogy with the isoelectronic PtC molecule. Ten bands involving vibrational levels up to Kv = 4 in the ground and excited states have been identified in the A1Pi-X1Sigma+ transition. This electronic transition has been previously observed by [A. J. Marr, M. E. Flores, and T. C. Steimle, J. Chem. Phys. 104, 8183-8196 (1996)]. To lower wavenumbers, five additional bands with R heads near 12 021, 12 816, 13 135, 14 136, and 15 125 cm-1 have been assigned as the 0-1, 3-3, 0-0, 1-0, and 2-0 bands, respectively, of the new A' 1Pi-X1Sigma+ transition. A rotational analysis of these bands has been carried out and equilibrium constants for the ground and excited states have been extracted. The Kv = 2 and 3 vibrational levels of the A' 1Pi state interact with the Kv = 0 and 1 levels of the A1Pi state and cause global perturbations in the bands. The ground state equilibrium constants for 193IrN are: omegae = 1126.176360(61) cm-1, omegaexe = 6.289697(32) cm-1, Be = 0.5001033(20) cm-1, alphae = 0.0032006(20) cm-1, and re = 1.6068276(32) Å. Copyright 1999 Academic Press.
ABSTRACT
The emission spectra of the A2Delta-X2Pi transition of SiH and SiD have been observed at high resolution using a Fourier transform spectrometer. The molecules were excited in a Si hollow cathode lamp by passing a discharge through a mixture of Ne and a trace of H2 or D2. The present data, combined with the previous infrared vibration-rotation measurements, have been used to determine improved molecular constants for the ground and excited states of SiH and SiD. Copyright 1998 Academic Press.
ABSTRACT
The emission spectrum of TaO, excited in a tantalum hollow cathode lamp, has been observed at high resolution using a Fourier transform spectrometer. In addition to previously known transitions, a number of new bands have been identified and assigned as belonging to two new electronic transitions: H2Pi1/2-X2Delta3/2 and K2Phi5/2-X2Delta3/2. A rotational analysis ofthe 0-0 and 0-1 bands of the H2Pi1/2-X2Delta3/2 transition and of the 0-1, 1-2, 0-0, 1-0, and 2-1 bands of theK2Phi5/2-X2Delta3/2 transition has been carried out, providing the following equilibrium constants for the ground X2Delta3/2 state:omegae = 1028.9060(15) cm-1, omegaexe = 3.58928(66) cm-1, Be = 0.40289737(139) cm-1, alphae = 0.00185445(83) cm-1, andre = 1.6873430(29) Å. The principal molecular constants for the H2Pi1/2 state are T00 = 20 634.32758 (40) cm-1,B0 = 0.3766867(31) cm-1, and r0 = 1.7450604(72) Å, while the equilibrium constants for the K2Phi5/2 state areomegae = 905.4549(15) cm-1, omegaexe = 3.67601(64) cm-1, Be = 0.37965102(36) cm-1, alphae = 0.00189370(21) cm-1, andre = 1.7382343(8) Å. Although the H2Pi1/2 and K2Phi5/2 states have been observed previously in matrix isolation experiments, our work on these states is the first in the gas phase. Copyright 1998 Academic Press.
ABSTRACT
The emission spectra of ScH and ScD have been investigated in the near infrared and visible using a Fourier transform spectrometer. The molecules were excited in a scandium hollow cathode lamp operated with neon gas and a trace of hydrogen or deuterium. Apart from the X 1 Sigma+ , B 1 Pi, C 1 Sigma+ , and G 1 Pi states reported previously [R. S. Ram and P. F. Bernath, J. Chem. Phys. 105, 2668-2674 (1996)], four additional new singlet electronic states A 1 Delta, D 1 Pi, E 1 Delta, and F 1 Sigma- have been identified below 21 000 cm-1 . The rotational analysis of several vibrational bands of the D 1 Pi-X 1 Sigma+ , D 1 Pi-A 1 Delta, E 1 Delta-B 1 Pi, E 1 Delta-A 1 Delta, and F 1 Sigma- -B 1 Pi transitions has been carried out and spectroscopic constants have been determined. The E 1 Delta state of ScH was not located because of the very weak intensity of the E 1 Delta-B 1 Pi and E 1 Delta-A 1 Delta transitions.
ABSTRACT
The infrared emission spectra of NaCl and KCl have been recorded at high resolution with a Fourier transform spectrometer. A total of 929 lines belonging to 8 vibrational bands, 1-0 to 8-7, for Na35 Cl, 252 lines of 1-0, 2-1, and 3-2 bands of Na37 Cl, and 355 lines of 1-0, 2-1, 3-2, and 4-3 bands of K35 Cl have been measured and combined with the existing microwave and millimeter-wave data to obtain a set of refined molecular constants. The data for Na35 Cl and Na37 Cl have also been fitted to determine the Dunham Yij constants and mass-reduced Dunham constants Uij . In one fit all Uij 's were treated as adjustable parameters while in a second fit only Ui 0 's and Ui 1 's were allowed to vary freely with the remaining Uij constants determined by the constraints imposed by the Dunham model. In addition, the internuclear potential energy parameters were determined by fitting the entire NaCl data set to the eigenvalues of the Schrodinger equation containing a parameterized potential energy function.
ABSTRACT
The emission spectrum of TiCl has been investigated in the 3000-12 000 cm-1 region at high resolution using a Fourier transform spectrometer. The bands were excited in a microwave discharge through a flowing mixture of TiCl4 and helium. The observed bands have been classified into three electronic transitions, C4Delta-X4Phi, G4Phi-X4Phi, and G4Phi-C4Delta. In the 3000-3500 cm-1 region, four bands with R heads at 3368.7, 3331.8, 3291.9, and 3243.4 cm-1 have been assigned as the 0-0 bands of the 1/2-3/2, 3/2-5/2, 5/2-7/2, and 7/2-9/2 subbands, respectively, of the C4Delta-X4Phi transition. To higher wavenumbers, four transitions with 0-0 R heads at 10 930.7, 10 921.3, 10 906.5, and 10 886.9 cm-1 have been assigned as the 3/2-3/2, 5/2-5/2, 7/2-7/2, and 9/2-9/2 subbands, respectively, of the G4Phi-X4Phi system of TiCl. Four additional bands with 0-0 R heads at 7568.8, 7596.4, 7622.2, and 7651.7 cm-1 have been identified as the 1/2-3/2, 3/2-5/2, 5/2-7/2, and 7/2-9/2 subbands of the G4Phi-C4Delta transition, respectively. A rotational analysis of a number of vibrational bands of these transitions has been obtained and molecular constants have been extracted. The lowest 4Phi state has been assigned as the ground state of TiCl, by analogy with our recent work on TiF (R. S. Ram and P. F. Bernath, J. Mol. Spectrosc., in press). The correspondence between the electronic states of TiCl, TiF, TiH, and Ti+ is also discussed. Copyright 1997 Academic Press. Copyright 1997Academic Press
ABSTRACT
The high-resolution spectrum of ZrCl has been investigated in emission in the region 3000-10 000 cm-1 using a Fourier transform spectrometer. The bands were excited in a microwave discharge through a flowing mixture of ZrCl4 and helium. New ZrCl bands observed in the interval 3600-4400 cm-1 have been assigned to a new C4Delta-X4Phi electronic transition. Four bands with R heads at 4305.7, 4208.0, 4064.7, and 3897.4 cm-1 have been assigned as the 0-0 bands of the 4Delta1/2-4Phi3/2, 4Delta3/2-4Phi5/2, 4Delta5/2-4Phi7/2, and 4Delta7/2-4Phi9/2 subbands. A rotational analysis of the 0-0, 1-1, and 2-2 vibrational bands of the four subbands has been obtained and molecular constants have been extracted. Although there is no proof that the lower 4Phi state is the ground state of ZrCl, we have labeled this transition as C4Delta-X4Phi, consistent with the corresponding near-infrared transition of TiCl (R. S. Ram and P. F. Bernath, J. Mol. Spectrosc., in press). Copyright 1997 Academic Press. Copyright 1997Academic Press
ABSTRACT
The emission spectrum of BN has been investigated in the 1800-9000 cm-1 region using a Fourier transform spectrometer. BN was formed in a microwave discharge of He with a trace of BCl3 and N2. The bands observed in the 3000-7800 cm-1 interval have been assigned as the b1Pi-a1Sigma+ transition, with the 0-0 band at 3513.99040(43) cm-1. This transition is analogous to the A1Piu-X1Sigma+g (Phillips) system of the isoelectronic C2 molecule. The rotational analysis of the 0-0, 1-1, 1-0, 2-1, 3-2, 2-0, 3-1, 4-2, and 4-1 bands has been obtained and the molecular constants for the b1Pi and a1Sigma+ states have been determined. A local perturbation has been observed in the v = 1 vibrational level of the b1Pi state near J = 18 caused by the interaction with the v = 3 vibrational level of the a1Sigma+ state. The principal equilibrium constants for the a1Sigma+ state are: omegae = 1705.4032(11) cm-1, omegaexe = 10.55338(52) cm-1, Be = 1.683771(10), alphae = 0.013857(16) cm-1, and re = 1.2745081(37) A. Although the b1Pi-a1Sigma+ transition has recently been seen in emission from boron nitride trapped in solid neon matrices [J. Chem. Phys. 104, 3143-3146 (1996)], our work represents the first observation of this transition of BN in the gas phase.
