XIAM

Version 2.5E of Holger Hartwig's IAM internal rotation program for up to three symmetric internal rotors and up to one quadrupolar nucleus


       This program has been kindly deposited by Heinrich Maeder of the Kiel group who is currently its custodian and can pass communications to Holger. Although Holger Hartwig can still be contacted he is now working outside academia. The downloads section first contains the unchanged program distribution package as received from Kiel, which is followed by some add-ons resulting from the experience in using this program in Warsaw.

        XIAM uses the extended Internal Axis Method proposed by Woods to treat internal rotation in an asymmetric top molecule and the principal features are:

  • up to three symmetric internal rotors
  • up to one quadrupolar nucleus with weakly interacting nuclear quadrupole coupling
  • centrifugal distortion up to sixth order for the pure rotational part
  • centrifugal distortion up to fourth order between internal and overall rotation
  • some top-top coupling terms for analysis of excited states of internal rotation
  • high speed of operation due to suitable basis transformations and matrix factorisation

        The recommended reference for citing the use of XIAM is:

        H.Hartwig and H.Dreizler, Z. Naturforsch 51a, 923-932 (1996).

        Definition of the empirical internal rotation-overall rotation distortion operator programmed into XIAM as terms Dpi2J, Dpi2K and Dpi2-:

        N.Hansen, H.Mader and T.Bruhn, Molec. Phys. 97, 587-595 (1999).


       
  The official XIAM distribution package
README.TXT Description of the distribution package for the program, which consists of the four files in the lefthand column of this table
XIAM-V25.TXT The documentation file
XIAM-25E.TGZ The gnuzipped tar archive of the source files as received from Kiel. In the Windows world this can be opened easily with a utility such as Windows Commander. Note that input is to carry extension .xi and output carries extension .xo
EXAMPLES.TGZ The gnuzipped tar archive containing input and output for several different examples. These are:

  XIAM extras from the webmaster
   
SAMPLE.XI A commented sample input file (for acetaldehyde), where some information from the documentation has been put in using the commenting options allowed by the program.

This commenting is only to serve as quick reference for the available options and not as a substitute reading the real documentation (and some papers!).

XIAM.EXE Win95/98/NT executable, compiled with the MSPS4 compiler, with array dimensioning as in the distribution listings. Since this is a pure number-crunching program the problems described in connection with graphics are not applicable.
   
  Modified XIAM
XIAMALL.FOR This is a derivative of the 'official' version of XIAM. This source file combines in one file all the constituent source modules for the program, with the exception of those directly below. Minimum descriptive commenting has been placed at the top of this source, and in several other places.

The changes to the original source are identified with zk or ! zk xiam4 in the comment field and these are either tweaks to the output formats or changes making the fitting statistics more directly comparable with those from SPFIT.

      

IAM_.FOR

IAMDATA_.FOR

MGETX_.FOR

These are source modules that are combined with the main source on compilation by means of the INCLUDE statements in XIAMALL.FOR. All three modules have to be placed in the same directory as XIAMALL.FOR.

The various PARAMETER statements at the top of the IAM_.FOR file serve to configure the program but as Holger Hartwig writes: please change the following parameters only if you really know what you are doing !

      

XIAM4.EXE An executable for a Pentium IV generated by the Intel Visual Fortran Compiler ver.9.1, using the options:

ifort -O3 -QxN -static -exe:xiam4 xiamall.for

This version is tailored for large single rotor datasets from mmw spectra (3000 lines and up to J=70) and will use up to 228 Mb of RAM so it should be run on a machine with at least 0.5 Gb.

   
  XA = Xiam to Ascp converter
XA.FOR

XA.EXE

This XIAM->ASCP converter will take XIAM output and produce a file in the .ASR standard that can be displayed by the stick display programs ASCP_L or ASCP.

At the moment XA only deals with output produced with the ints 3 option, the rigid rotor lines are disregarded, and the intensity is taken from the total column. The internal rotation labels Sn Vm Bk are placed as n,m,k into the last three quantum numbers of the lower state.

 

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ERHAM

Peter Groner's Effective Rotational HAMiltonian program for molecules with up to two periodic large-amplitude motions


        This program has been kindly deposited by its author, Peter Groner, from Department of Chemistry at the University of Missouri, Kansas City (updated to a new version in July 2013)

        ERHAM sets up and solves the "Effective rotational Hamiltonian for molecules with two periodic large-amplitude motions". It allows to fit spectroscopic constants to observed transition frequencies (usually to experimental precision) and to predict the spectrum.

        The reference for citing the use of ERHAM is: P. Groner, J. Chem. Phys. 107, 4483-4498 (1997).
        A review of the theory and the performance of the effective rotational Hamiltonian is also available: P. Groner, J. Mol.Spectrosc. 278, 52-67 (2012).
           

       

        Principal features:

  • One or two internal rotors, not restricted to threefold rotors
  • Models and symmetry groups:
    1. Equivalent rotors: C2v, C2, Cs
    2. Non-equivalent rotors: Cs, C1
    3. Single rotor: Cs, C1
  • max(J) = 120
  • Number of transitions in fit < 8191
  • Modular input for “tunneling parameters”
  • Tunneling energy parameters eqq
  • Tunneling contributions to rotational and distortion constants
  • Quartic and sextic centrifugal distortion constants (A-reduction); higher order CD terms may be defined using the “tunneling parameter input” which can also be used to define terms for the S-reduction
  • Global fit of several non-interacting vibrational states to the same r-vector parameters
  • high speed of operation due to suitable basis transformations and matrix factorisation


        ERHAM has been used in numerous investigations, which can be treated as worked examples for the various areas of its applicability.  Published applications involving its author (GS = ground state, ETS = torsional excited state):

  • Dimethyl ether (GS): P. Groner et al., Astrophys. J. 500, 1059-1063 (1998)
  • 3-Methyl-1,2-butadiene (global fit of GS and 1st ETS): S. Bell et al., J. Phys. Chem. A 104, 514-520 (2000)
  • Acetone (GS): P. Groner et al., Astrophys. J. Suppl. Ser. 142, 145-151 (2002)
  • Ethyl methyl ether (GS, nonequivalent): U. Fuchs et al., Astrophys. J. Suppl. Ser. 144, 277-286 (2003)
  • Dimethyl diselenide (GS, isotopomers with C2 or C1 symmetry): P. Groner et al., J. Mol. Spectrosc. 226, 169-181 (2004)
  • Acetone-13C (equivalent, non-equivalent): F. J. Lovas & P. Groner, J. Mol. Spectrosc. 236, 173-177 (2006)
  • Acetone (1st ETS): P. Groner et al., J. Mol. Struct. 795, 173-178 (2006)
  • Methyl carbamate (1 rotor, GS) P. Groner et al., Astrophys. J. Suppl. Ser. 169, 28-36 (2007)
  • Methyl formate-1-13C (1 rotor, GS) A. Maeda et al., Astrophys. J. Suppl. Ser. 175, 138-146 (2008)
  • Acetone (2nd ETS): P. Groner et al., J. Mol. Spectrosc. 251, 180-184 (2008)
  • CHClF2-H2O Chlorodifluoromethane-water (1 top - two-fold, GS): B.J. Bills et al., J. Mol. Spectrosc. 268, 7-15 (2011)
  • 1,1-difluoroacetone (1 top, GS): G.S. Grubbs, II et al.,  J. Mol. Spectrosc. 280, 21-26 (2012)
  • Dimethyl ether-d1 (1 top, 2 conformers, GS): C. Richard et al., A & A 552, A117 (2013)


Other authors:

  • Propane (GS & 2 ETS) Drouin et al. J. Mol. Spectrosc. 240, 227-237 (2006)
  • Pyruvic acid (1 rotor, GS & several non-interacting excited states) Z. Kisiel et al., J. Mol. Spectrosc. 241, 220-229 (2007)
  • Methyl formate-12C & -1-13C  (1 rotor, ETS) A. Maeda et al. J. Mol. Spectrosc. 251, 293-300 (2008)
  • Pyruvic acid (1 rotor, GS & several non-interacting excited states) Z. Kisiel et al., J. Mol. Spectrosc. 241, 220-229 (2007)
  • Dimethyl ether (GS) Endres et al. A&A 504, 635-640 (2009)
  • Pyruvonitrile (1 rotor, GS & several non-interacting excited states) Krasnicki et al., J. Mol. Spectrosc. 260, 57-65 (2010)
  • Dimethyl carbonate (GS): F.J. Lovas, et al., J. Mol. Spectrosc. 264, 10-18 (2010)
  • Isopropenyl acetate (GS): H.L.V. Nguyen et al., J. Mol. Spectrosc. 264, 120-124 (2010)
  • Dimethyl sulfate (GS): L.B. Favero et al., Chem. Phys. Lett. 517, 139-145 (2010)
  • CF3(CF2)3O-CH3 & (CF3)2CFCF2OCH3 (1 top each, GS): G. S. Grubbs, II, et al., J. Phys. Chem. A, 115, 1086–1091 (2011)


       

The ERHAM package, version v16g-R3 of July 2013
ERHAM.FOR Source listing. 

This version of the program was described in a dedicated talk WH01 at the 68th OSU International Symposium on Molecular Spectroscopy, June 17-21, 2013.  Here is a PDF version of this presentation, while the original is available here.
ERHAM.EXE Executable for Win32 systems
ERHAM.TXT Documentation file.
ac10x-r3.in
ac10x-r3.out
ac10x-r3.cat
Input and output for acetone, lowest excited state demonstrating some features specific to this version.  The (abbreviated) .cat file contains predictions in the format of the jpl catalog.


  Legacy:
ERHAM.FOR
ERHAM.EXE
ERHAM.TXT
Source listing, Win32 executable and the documentation file for ERHAM package, version v16g-R1 of Oct2009
   
  Input and output examples
AC13C1G.IN
AC13C1G.OUT
Acetone 13C1 ground state.
DMAG.IN
DMAG.OUT
Dimethylallene, Demaison et al., J.Mol.Spectrosc. 40, 445-460 (1971); 68, 97-113 (1977)
DMDSEG.IN
DMDSEG.OUT
Dimethyl diselenide 78Se80Se.

  ERHAM extras from the webmaster
   
ERHCONST.TXT Indices and names for the ERHAM constants
ERHAM_AABS.TXT

     

How to use ERHAM with AABS
  ERHAMZ = tweaked version of ERHAM
ERHAMZ.FOR

ERHAMZ.EXE

This is a derivative of the 'official' version of ERHAM above with tweaks to some FORMAT statements and with additional code for picking out worst lines in the dataset.

All modifications are marked with the string ! zk in the comment columns.

The executable is for a Pentium IV as generated by the Intel Visual Fortran Compiler ver.9.1, using the options :

ifort -O3 -QxN -static erhamz.for

   
  LINERH = LIN to ERHam converter
LINERH.FOR
LINERH.EXE
LINERH.INP
Utility to convert lines from the .LIN format of SPFIT to a block suitable for use in ERHAM input file. The steering file LINERH.INP holds pertinent control information (to be reedited) and should reside in the same directory as the input file.
   
  ERHASR = ERHam to ASR converter
ERHASR.FOR
ERHASR.EXE
ERHASR.INP
Utility to convert ERHAM predictive output into the form suitable for stick display programs ASCP_L or ASCP. The steering file ERHASR.INP holds pertinent control information (to be reedited) and should reside in the same directory as the input file.
   
  ERHRES = ERHam to RES converter
ERHRES.FOR
ERHRES.EXE
ERHRES.INP
Utility to convert ERHAM output into the form compatible with the .RES output of ASFIT or PIFORM with various enhanced readability features. The file DMAG.RES is an example of using ERHAM followed by ERHRES.

The .RES file can be used by the program AC of the AABS package for making dataset distribution plots.

In addition to the .RES file ERHRES will also generate a .LIN file for possible use by SPFIT or by the ASCP_L display program of AABS.

NOTE: ERHAM allows empty lines to be placed between transitions, which are transferred by ERHRES to both the .RES output, and as appropriate comments in the .LIN output, for later use by PIFORM.

   
 

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BELGI

The BELGian Internal Rotor Program

of Isabelle Kleiner et al.


        This program has been kindly deposited by its principal author, Isabelle Kleiner, from Laboratoire Interuniversitaire des Systèmes Atmosphériques, LISA, (Université paris 7 et Paris 12 et CNRS, Créteil, France).  The current BELGI repository consists of three complementary packages:
  • BELGI-Cs - program for molecules containing an internal rotor (of C3v symmetry) which can turn relative to the rest of the molecule (of Cs symmetry)
  • BELGI-C1 - program for molecules containing an internal rotor (of C3v symmetry) which can turn relative to the rest of the molecule (with no symmetry)
  • several utility programs for both versions of BELGI


This program has a long history, detailed in the
readme, and the authors (in chronological order) are: 

  • I. Kleiner from Laboratoire Interuniversitaire des Systèmes Atmosphériques, LISA, (Université paris 7 et Paris 12 et CNRS, Créteil, France)
  • M. Godefroid from the "Laboratoire de Chimie Quantique et Photophysique" , Free University of Brussels (Belgium),
  • J. T. Hougen from the National Institute for Standards and Technology (NIST, Gaithersburg, USA),
  • L-H. Xu from Department of Physical Sciences, University of New Brunswick,
  • J. Ortigoso from Instituto de Estructura de la Materia, CSIC (Madrid, Spain),
  • V. Ilyushin from the Radio Astronomy Institute of NASU, Kharkov (Ukraine)
  • M. Carvajal-Zaera from the Departamento de Fisica Aplicada, University of Huelva (Spain)
       BELGI uses the rho-axis system method (RAM), and allows the user to calculate and fit the energies of transitions for molecules containing an internal rotor (of C3v symmetry) which can turn relative to the rest of the molecule (of Cs symmetry).(BELGI-Cs) or a molecular frame devoid of symmetry (BELGI-C1).


       The reference for citing the use of BELGI-Cs is:

  • J. T. Hougen, I. Kleiner and M. Godefroid, J. Mol. Spectrosc., 163, 559-586 (1994). 

       Extensive listing of previous applications of  BELGI-Cs is available and those papers contain many different examples of the use of this program.

        Principal characteristics of BELGI-Cs:

  • Fit one internal rotor of C3v symmetry (like a CH3 group), while the rest of the molecule possesses a plane of symmetry (Cs).
  • Jmax = 30
  • Up to 80000 lines to fit or to calculate
  • Up to 80 parameters of fit in each vibrational state
  • Up to 2 vibrational states
  • A two-step diagonalisation with:
    1. the diagonalisation of a 21x21 torsional matrix for each K and s value (K is the projection of J on the symmetry axis of the molecule and s is the symmetry with s = 0 for the A states and s = 1 for the E states), and
    2. the diagonalisation of the rotation, centrifugal distortion and rotation-torsion coupling terms of the Hamiltonian (dimension (9)*(2J+1) x (9)*(2J+1))
  • A global fit of the A and E species corresponding to ALL the torsional levels (up to the 9th torsional state vt 0, 1…8)


       The references for citing BELGI-C1 are:

  1. I. Kleiner and J. T. Hougen, J. Chem. Phys. 119, 5505 (2003) 
  2. R. J. Lavrich, A. R. Hight Walker, D. F. Plusquellic, I. Kleiner, R. D. Suenram, , J. T. Hougen and G. T. Fraser, J. Chem. Phys. , 119, 5497-5504 (2003).

        You can also check the listing and a listing of previous applications of  BELGI-Cs is given here.       
Principal characteristics of BELGI-C1:

  • can fit one internal rotor of C3v symmetry (like a CH3 group), the rest of the molecule may not possess a plan of symmetry (C1). Complex algebra used.
  • Jmax = 30
  • Max 20000 lines to fit or to calculate
  • Max 80 parameters to fit in each vibrational states
  • A two-step diagonalisation with:
    1. the diagonalisation of a 21x21 torsional matrix for each K and s value (K is the projection of J on the symmetry axis of the molecule and s is the symmetry with s = 0 for the A states and s =1 for the E states) and
    2. the diagonalisation of the rotation, centrifugal distortion and rotation-torsion coupling terms of the Hamiltonian (dimension (9)*(2J+1) x (9)*(2J+1))
  • A Global fit of the A and E species corresponding to ALL the torsional levels (up to the 9th torsional state vt 0, 1…8)


       
  The BELGI-Cs package
BELGI-Cs.FOR Source listing. The program uses two routines from the IMSL library that have to be provided at compilation time. The two routines are DLSVRR for singular value decomposition, and DLINRG for matrix inversion.
BELGI-Cs.EXE Executable for Win32 systems. The program assumes that the input is always in the file input.txt, and writes to the default output device, which is normally the screen. If you want to save the output to a file, say belgi.out, use the command

belgi-cs>belgi.out

The program may spend a lot of time without apparent output, so you can use the Task Manager to check CPU usage. It also creates a file called DAT for its own use - this file is not deleted by the program on completion of execution but will be replaced on another run of BELGI.

README_Cs.PDF The main documentation file for the program, which includes discussion of its features, internal structure, format of the input file, the meaning of the parameters, and concludes with a special section on the history of BELGI development and applications.
CONSTANTS.TXT Table summarising the terms in the vibration-rotation Hamiltonian that can be used in BELGI: the angular momentum operators and the identifiers for the associated constants.
   
  Input and output examples:
INPUT.TXT

 

Input file for methyl carbamate, H2NC(O)OCH3, ground and first torsional states, J. Mol. Spectrosc., 240, 127 (2006).
MECARB.OUT

     

Output file for methyl carbamate produced from the input above.
   The BELGI-C1 package
BELGI-C1.FOR Source listing. The program uses two routines from the IMSL library that have to be provided at compilation time. The two routines are GETTIM for timing and DLINRG for matrix inversion.
BELGI-C1.EXE Executable for Win32 systems. Run in the same way as described for BELGI-Cs above.  The program assumes that the input is always in the file input.txt, and writes to the default output device, which is normally the screen. If you want to save the output to a file, say belgi.out, use the command

belgi-c1>belgi.out

The program may spend a lot of time without apparent output, so you can use the Task Manager to check CPU usage. It also creates a file called DAT for its own use - this file is not deleted by the program on completion of execution but will be replaced on another run of BELGI.

README_C1.PDF Documentation.  Only the particularity for the C1 code is described here, while for more general information, see also the read-me file for BELGI-Cs
CONSTANTS.TXT The list of parameters which can be floated



Input and output examples:
INPUT.TXT Input file for N-acetyl alanine methyl ester molecule (ADME) ground torsional state ( J. Chem. Phys. 125, 104312 (2006))
ADME.OUT Output file for the input above.



 Utility programs for BELGI




CONVERT =  to convert JKaKc quantisation (from input format used by XIAM) into format of BELGI
convert-a.for
convert-a.exe
Source and WIN32 executable for the A-symmetry species.  Just run the executable by its name.  Input and output are from files with compulsory names:

input file = XIAM-data-A-sept08.txt
output file = out-BELGI-A-sept08.txt

convert-e.for
convert-e.exe
Source and WIN32 executable for the E-symmetry species.    Just run the executable by its name.  Input and output are from files with compulsory names:

input file = XIAM-data-E-sept08.txt
output file = out-BELGI-E-sept08.txt



ABC =  to convert A,B,C,Dab,Dac,Dbc from BELGI (RAM quantities) to A,B,C (PAM quantities)
abc.for
abc.exe
Source and WIN32 executable.  This program is to be executed using the pipeline operation.
 
For screen output use the command:
abc<input_file_name

For disk output use the command: abc<input_file_name>output_file_name

Sample input file = RAMabcdADME
Sample output file = PAM-ADME



MOMENTS =  to calculate guess input values for BELGI from masses and Cartesian coordinates of atoms in the molecule
moments.for
moments.exe
Source and WIN32 executable.  Just run the executable by its name.  Input and output are from files with compulsory names:

input file = TAPE5.txt
output file = TAPE6.txt


 

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RAM36

Vadim Ilyushin's program using the  Rho Axis Method for 3 and 6 fold barriers


        This program has been kindly deposited by its author, Vadim Ilyushin, from the Institute of Radio Astronomy of the National Academy of Sciences of the Ukraine in Kharkov.  The program is a derivative of  BELGI and is characterised by considerable increase in the speed of operation.  The program was written in collaboration with Dr. J.T. Hougen (of NIST) and the effectiveness of this collaboration was considerably enhanced by the NIST exchange visitor  program, and the help of this NIST program is therefore gratefully acknowledged by the author.
 

        RAM36 is designed to deal with two general internal rotation cases: 
  • Sixfold rotation case with a C3v internal rotor and a C2v frame (such as toluene and nitromethane)
  • Threefold rotation case with a C3v internal rotor and a Cs frame (such as acetic acid, acetamide or methyl formate)



        The reference for citing the use of RAM36 is:

  • V.V. Ilyushin, Z. Kisiel, L. Pszczółkowski, H. Mäder, J.T. Hougen,  “A New Torsion-Rotation Fitting Program for Molecules with a Six-Fold Barrier: Application to the Microwave Spectrum of Toluene”, Journal of Molecular Spectroscopy 259, 26-38 (2010) 

        This paper describes both the program and its application to the analysis of the lowest m-states in the rotational spectrum of toluene, which is a rather demanding low-barrier case. Another example of application of RAM36 can be found in:    

  • V.V. Ilyushin, L.B. Favero, W.Caminati, J-U. Grabow “Intertorsional Interactions Revealing Absolute Configurations: The V6 Internal Rotation Heavy-Top Case of Benzotrifluoride”, ChemPhysChem 11, 2589 – 2593.(2010). 

        An example of the use of RAM36 for a problem with a threefold barrier is described in:

  • V.Ilyushin, R.Rizzato, L.Evangelisti, G.Feng, A.Maris, S.Melandri, W.Caminati Almost free methyl top internal rotation: rotational spectrum of 2-butynoic acid, Journal of Molecular Spectroscopy  267, 186 - 190 (2011).


       
  The RAM36 package, version Dec 2012
RAM36.FOR Source listing.  

RAM36 uses several routines from the LAPACK library that have to be
provided at compilation time. These routines are DSTEQR, DSYTRD, DORGTR,
DGETRF, DGETRI, and DGESVD.  In order to achieve the highest performance of the program it is recommended to use specific-processor-optimized versions of the LAPACK library like Intel Math Kernel Library (MKL) or AMD Core Math Library (ACML).

RAM36 also uses the DSBRDT routine from the Successive Band Reduction (SBR) package [ C.H. Bischof, B. Lang, X.-.B. Sun, ACM Trans. Math. Software 26 (2000) 602-616.].  The source code is provided in the end of this file.

RAM36.EXE Executable for Windows systems compiled with Intel Visual Fortran v.10 and making some use of the Intel multicore processor architecture.

The input should be in the file input.txt. This name is fixed so you might like to keep a copy of this file under a name related to the molecular problem.

The program should be run from the command prompt window opened in the directory containing the input file. Use the pipeline command:
        ram36>output
whereupon the results will be written to the file
output.  In this case the name of the output file is up to the user.

READMERAM36.PDF Documentation file for RAM36.
   
  Input and output examples
INPUT_TOLUENE OUT_TOLUENE 

The input and output for the sixfold barrier case toluene as in the reference paper.


INPUT_2BA
OUT_2BA 
The input and output for the threefold barrier case of 2-butynoic acid.

  RAM36 extras from the webmaster
   
RAM36_AABS.TXT

     

Instructions on how to use RAM36 with AABS
  VIFORM = reformatting of the fit output from RAM36
VIFORM.FOR

VIFORM.EXE

Formatter of output from RAM36, which should be placed in file called  molnam.out, where the choice of the string  molnam  is up to the user. 

VIFORM will produce:
  • files  molnam_original.lin  and  molnam_frequency.lin,   which are .LIN type files in the standard of the SPFIT program.  Any of these can be used by AABS as a data file for storing measurements.
  • files  molnam_original.res  and  molnam_frequency.res,  which are similar to the .RES type files in the standard of the PIFORM program containing printable blocks of obs.-calc. lines.  The first file also contains some statistics and lists the worst fitting lines.
  • file  molnam.con  with parameters of fit and the errors written in the standard convention for tabulating such values, and with a readable correlation matrix
TOLUENE.CON TOLUENE_ORIGINAL.RES
TOLUENE_ORIGINAL.LIN 
Some of the output file produced by VIFORM if the  out_toluene  file above is copied to  toluene.out.
Note that the various annotations on transitions are preserved.
   
  VADASR = reformatting of predictive output from RAM36
VADASR.FOR

VADASR.EXE

Utility to convert RAM36 predictive output into the form suitable for the stick display program ASCP_L.

This program requires predictive output from RAM36, obtained by setting the first switch in the seventh line after the &&&END line to +1 or -1.  The PREDICTVT0.TXT file from RAM36 then has to be copied to file VADASR.INP..  If file PREDICTVT1.TXT was also generated then this can be appended to VADASR.INP..

The output will be written to file VADASR.OUT containing all of the predicted lines, as well as to individual files for each m state called:
m0.asr, m1.asrm2.asr, m3.asr , m-3.asr ,... up to m-6.asr .

TOL_ASCPL.INP The control file for ASCP_L  (option 2) allowing all of the m substate files produced for toluene to be read and displayed.  This file can be modified as necessary.
   
  LINVAD = converter from .LIN standard of SPFIT to frequency data block used by RAM36
LINVAD.FOR
LINVAD.EXE

LINVAD.INP

Utility to convert lines from the .LIN format of SPFIT to a block suitable for use in the input file to RAM36.
The steering file LINVAD.INP holds pertinent control information (to be reedited) and should reside in the same directory as the input file.
   
 

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SPFITint

Can SPFIT be used to fit internal rotation ?


        This is a recurring question and it is quite a reasonable one in view of the power of SPFIT and of the general nature of the way in which it allows the Hamiltonian to be constructed.

        In short, the answer is YES, but the treatment may be less direct than you might like.  Two alternative approaches are possible:
  • METHOD 1: Fourier series expansion based on the Mathieu equation description of the Internal Axis System (IAS)  Hamiltonian for internal rotation [1].  The .PAR parameter file for SPFIT is set up by means of two preprocessor programs, first MOIAM (input file .INP),  then IAMCALC (input file .IAM). This results in a .PAR file with an extensive set of linked parameters.  This file is completely unreadable and its size can run to many Megabytes. Fortunately, in the final SPFIT output these expansions are brought together into the original leading parameters as specified in the .IAM file.  Direct program documentation  seems to be limited to that in moiam.c and iamcalc.c source codes, but there are quite a number of published applications to serve as worked examples.  These include studies of HNO3 [2], methyl formate [3], propane [4], acetaldehyde [5], hydroxyacetone [6], and methyl carbamate [7].  Note that in [4] there is also a comparison of this way of using SPFIT with ERHAM.

  1. H.M.Pickett,  J,Chem.Phys.107, 6732 (1997)
  2. D.T.Petkie, T.M.Goyette, P.Helminger, H.M.Pickett, F.C.De Lucia, J.Mol.Spectrosc. 208, 121 (2001); this appears to be the first explicit mention of MOIAM and IAMCALC in a publication.
  3. Methyl Formate = species  c060003 in jpl spectral line catalog: PDF entry (includes a short description of IAMCALC),  IAM file, PAR file (warning: 18MB) , LIN file
  4. B.J.Drouin, J.C.Pearson, A.Walters, V.Lattanzi, J.Mol.Spectrosc. 240, 227 (2006) = propane, species c044013 in jpl spectral line catalog: PDF entryPAR file, LIN file
  5. Acetaldehyde = species c044003 in jpl spectral line catalog: PDF entry (includes a short description of IAMCALC),  IAM file, PAR file (warning: 8.8MB) , LIN file
  6. A.J.Apponi, J.J.Hoy, D.T.Halfen, L.M.Ziurys, Astrophy. J. 652, 1787 (2006) = Hydrohxyacetone, species c074003 in jpl spectral line catalog: PDF entry,  PAR file, LIN file
  7. Methyl Carbamate = species c075004 in jpl spectral line catalog: PDF entry (includes a short description of IAMCALC),  PAR file (warning: 4MB), LIN file


  • METHOD 2: Effective single state fits based on perturbation approximations.  These will only work sensibly in specific cases but may be all that is required for the relatively small, low-J data sets obtained in supersonic expansion measurements.  The approach is based on the Principal Axis Method approach (PAM) and depends on the fact that for a sizable threefold barrier the A states are sufficiently well treatable by the standard asymmetric rotor Hamiltonian.  For the E states the torsion-rotation interaction may be sufficiently well described by terms of the type DaPa and their centrifugal distortion expansion, with the choice of terms depending on the orientation of the internal rotation axis relative to the inertial axes.  These terms have direct SPFIT indices.  The approach has been well described and used to treat supersonic expansion data for o-chlorotoluene [1], and later for much higher-J, mmw data for pyruvic acid [2] and pyruvonitrile [3].  The discussion in Ref.[1] constitutes a nice tutorial in the use of the method, including how to derive the barrier height V3 from such fits by using tabulated perturbation coefficients in Appendix C of  [4].  In [2-3] this method is compared to the results from XIAM and ERHAM and the advantages and disadvantages of this simple approach are discussed.  The supplementary material for [2-3] also contains the input data files for SPFIT.
  1. D.Gerhard, A.Hellweg, I.Merke, W.Stahl, M.Baudelet, D.Petitprez, G.Wlodarczak, J.Mol.Spectrosc. 220, 234  (2003).
  2. Z.Kisiel, L.Pszczolkowski, E.Bialkowska-Jaworka, S.B.Charnley, J.Mol.Spectrosc. 241, 220 (2007).
  3. A.Krasnicki, Z.Kisiel, L.Pszczolkowski J.Mol.Spectrosc. 260, 57 (2010).
  4. D.R.Herschbach, J.Chem.Phys. 31, 91 (1959).

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