Vibrational spectroscopies

Calculations of normal modes are performed with the aid of geomeTRIC.

The associated IR spectrum is calculated by default also when Raman or resonance Raman calculations are requested except if specified otherwise.

Infrared¶

Python script

import veloxchem as vlx

xyz="""
... 
"""

molecule = vlx.Molecule.read_xyz_string(xyz)
basis = vlx.MolecularBasis.read(molecule, 'def2-svp')

scf_drv = vlx.ScfRestrictedDriver()
scf_drv.filename = 'mol-ir'
scf_drv.xcfun = 'b3lyp'
results = scf_drv.compute(molecule, basis)

vib_drv = vlx.VibrationalAnalysis(scf_drv)
vib_drv.do_ir = True
scf_drv.filename = 'mol-ir'
vib_results = vib_drv.compute(molecule, basis)

Text file

@jobs
task: vibrational
@end

@method settings
xcfun: b3lyp
basis: def2-svp
@end

@vibrational
do_ir: yes
@end

@molecule
charge: 0
multiplicity: 1
xyz:
...                     
@end

Raman¶

Python script

import veloxchem as vlx

xyz="""
... 
"""

molecule = vlx.Molecule.read_xyz_string(xyz)
basis = vlx.MolecularBasis.read(molecule, 'def2-svp')

scf_drv = vlx.ScfRestrictedDriver()
scf_drv.filename = 'mol-raman'
scf_drv.xcfun = 'b3lyp'
results = scf_drv.compute(molecule, basis)

vib_drv = vlx.VibrationalAnalysis(scf_drv)
vib_drv.do_ir = False
vib_drv.do_raman = True
vib_drv.filename = 'mol-raman'
vib_results = vib_drv.compute(molecule, basis)

Text file

@jobs
task: vibrational
@end

@method settings
xcfun: b3lyp
basis: def2-svp
@end

@vibrational
do_raman: yes
@end

@molecule
charge: 0
multiplicity: 1
xyz:
...                     
@end

Resonance Raman¶

Python script

import veloxchem as vlx

xyz="""
... 
"""

molecule = vlx.Molecule.read_xyz_string(xyz)
basis = vlx.MolecularBasis.read(molecule, 'def2-svp')

scf_drv = vlx.ScfRestrictedDriver()
scf_drv.filename = 'mol-reson-raman'
scf_drv.xcfun = 'b3lyp'
results = scf_drv.compute(molecule, basis)

vib_drv = vlx.VibrationalAnalysis(scf_drv)
vib_drv.do_ir = False
vib_drv.do_raman = True
vib_drv.filename = 'mol-reson-raman'
vib_results = vib_drv.compute(molecule, basis)

Text file

@jobs
task: vibrational
@end

@method settings
xcfun: b3lyp
basis: def2-svp
@end

@vibrational
do_resonance_raman: yes
frequencies: 0.05-0.10 (0.05)
@end

@molecule
charge: 0
multiplicity: 1
xyz:
...                      
@end