diff --git a/Cantera/src/spectra/Makefile.in b/Cantera/src/spectra/Makefile.in
new file mode 100644
index 000000000..3e022268f
--- /dev/null
+++ b/Cantera/src/spectra/Makefile.in
@@ -0,0 +1,84 @@
+#/bin/sh
+###############################################################
+#  $Author$
+#  $Date$
+#  $Revision$
+#
+#  Copyright 2007 California Institute of Technology
+#
+###############################################################
+
+.SUFFIXES :
+.SUFFIXES : .cpp .d .o .h
+
+INCDIR = ../../../build/include/cantera/kernel
+INSTALL_TSC = ../../../bin/install_tsc
+do_ranlib = @DO_RANLIB@
+
+debug_mode = @CANTERA_DEBUG_MODE@
+ifeq ($(debug_mode), 1)
+   DEBUG_FLAG=-DDEBUG_MODE
+else
+   DEBUG_FLAG=
+endif
+
+PIC_FLAG=@PIC@
+
+CXX_FLAGS = @CXXFLAGS@ $(LOCAL_DEFS) $(CXX_OPT) $(PIC_FLAG) $(DEBUG_FLAG)
+
+SPECTRA_OBJ = rotor.o
+
+SPECTRA_H   = rotor.h
+
+CXX_INCLUDES = -I. @CXX_INCLUDES@ -I../base
+LIB = @buildlib@/libctspectra.a
+
+DEPENDS = $(SPECTRA_OBJ:.o=.d)
+
+all: $(LIB) .depends
+	@(@INSTALL@ -d $(INCDIR))
+	@(for lh in $(SPECTRA_H) ; do \
+	  $(INSTALL_TSC) "$${lh}" $(INCDIR) ; \
+	done)
+%.d:
+	@CXX_DEPENDS@ $(CXX_INCLUDES) $*.cpp > $*.d
+
+.cpp.o:
+	@CXX@ -c $< $(CXX_FLAGS) $(CXX_INCLUDES)
+
+$(LIB): $(SPECTRA_OBJ) $(SPECTRA_H)
+	@ARCHIVE@ $(LIB) $(SPECTRA_OBJ) > /dev/null
+ifeq ($(do_ranlib),1)
+	@RANLIB@ $(LIB)
+endif
+
+clean:
+	@(for lh in dummy.h $(SPECTRA_H) ; do \
+            th=$(INCDIR)/"$${lh}" ; \
+	    if test -f "$${th}" ; then \
+	      $(RM) "$${th}"  ; \
+              echo "$(RM) $${th}" ; \
+            fi \
+	  done)
+	@(if test -f $(LIB) ; then \
+	    $(RM) $(LIB) ; \
+            echo "$(RM) $(LIB)" ; \
+          fi)
+	$(RM) *.o *~  .depends *.d
+	(if test -d SunWS_cache ; then \
+           $(RM) -rf SunWS_cache ; \
+         fi )
+
+depends:
+	@MAKE@ .depends
+
+.depends: $(DEPENDS)
+	cat $(DEPENDS) > .depends
+
+TAGS: 
+	etags *.h *.cpp
+
+ifeq ($(wildcard .depends), .depends)
+include .depends
+endif
+
diff --git a/Cantera/src/spectra/rotor.cpp b/Cantera/src/spectra/rotor.cpp
new file mode 100644
index 000000000..394c620de
--- /dev/null
+++ b/Cantera/src/spectra/rotor.cpp
@@ -0,0 +1,51 @@
+
+#ifdef WIN32
+#pragma warning(disable:4786)
+#pragma warning(disable:4503)
+#endif
+
+#include "ct_defs.h"
+#include "rotor.h"
+
+namespace Cantera {
+
+    /*
+     * @param mu  reduced mass in kg
+     * @param re  bond length in meters
+     * @dipoleMoment permanent dipole moment in ...
+     */
+    Rotor::Rotor(doublereal Bv, doublereal dipoleMoment, 
+        doublereal Dv, doublereal Hv ) : m_Bv(Bv), 
+                                         m_Dv(Dv),
+                                         m_Hv(Hv),
+                                         m_dipole(dipoleMoment) {}
+
+    // energy in wavenumbers
+    doublereal Rotor::energy_w(int J) {
+        int jjp1 = J*(J + 1);
+        return jjp1*(m_Bv + jjp1*(m_Hv*jjp1 - m_Dv));
+    }
+
+    doublereal Rotor::degeneracy(int J) {
+        return 2*J + 1;
+    }
+
+    doublereal Rotor::partitionFunction(doublereal T, int cutoff) {
+        int j = 0;
+        if (cutoff < 0) cutoff = 100;
+        doublereal dsum = 0.0, sum = 0.0;
+        for (j = 0; j < cutoff; j++) {
+            dsum = degeneracy(j)*exp(-Planck*energy_w(j)/(Boltzmann * T));
+            sum += dsum;
+        }
+        return sum;
+    }
+
+    doublereal Rotor::frequency(int J_lower, int J_upper) {
+        return (energy_w(J_upper) - energy_w(J_lower));
+    }
+}
+
+
+
+
diff --git a/Cantera/src/spectra/rotor.h b/Cantera/src/spectra/rotor.h
new file mode 100644
index 000000000..0aa699258
--- /dev/null
+++ b/Cantera/src/spectra/rotor.h
@@ -0,0 +1,60 @@
+#ifndef CT_ROTOR
+#define CT_ROTOR
+
+#include "ct_defs.h"
+
+namespace Cantera {
+
+    class Rotor {
+    public:
+        Rotor() {}
+        virtual ~Rotor() {}
+
+        /*
+         */
+        Rotor(doublereal Bv, doublereal dipoleMoment = 0.0, 
+            doublereal Dv = 0.0, doublereal Hv = 0.0);
+
+
+        // energy in wavenumbers
+        doublereal energy_w(int J);
+
+        doublereal degeneracy(int J);
+
+        doublereal partitionFunction(doublereal T, int cutoff=-1);
+
+        doublereal frequency(int J_lower, int J_upper);
+
+    protected:
+
+        doublereal m_Bv;
+        doublereal m_Dv;
+        doublereal m_Hv;
+        doublereal m_dipole;
+    };
+
+    /** convert from Hz to wavenmbers */
+    inline doublereal hz_to_wnum(doublereal freq) {
+        return freq/(100.0*lightSpeed);
+    }
+
+    inline doublereal wnum_to_J(doublereal w) {
+        return Planck * w * 100.0 * lightSpeed;
+    }
+
+    inline doublereal J_to_wnum(doublereal e) {
+        return e /(Planck * 100.0 * lightSpeed);
+    }
+
+    inline doublereal wnum_to_eV(doublereal w) {
+        return Planck * w * 100.0 * lightSpeed / ElectronCharge;
+    }
+
+    inline doublereal eV_to_wnum(doublereal e) {
+        return e * ElectronCharge / (Planck * 100.0 * lightSpeed);
+    }
+}
+
+#endif
+
+